Lotus Europa Community
Lotus Europa Forums => Garage => Topic started by: brucelotus26r on Sunday,March 12, 2017, 10:23:05 AM
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How is the best way to bleed the brakes on my twin cam all shock. Any tricks
After resealing the trans, having the gas tanks clean & sealed and cleaning up & repainting the T part of the frame.
I took the car for a test drive and the brake pedal went 1/2 to the floor. I tried bleeding the brakes and they got worse so I rebuilt the master cylinder and bled them, better, but not as good as I was hoping for?
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Bruce, do you have the boosters in place or not? I gave you that blog/article I wrote about the escapade I had bleeding and rebuilding my brake system. Bleeding "should" be straightforward and typical of any car, but I used an air chuck on my master cylinder (low psi) to do the trick.
Did you use original configuration concerning the master cylinder, the push rod, original bore, etc.?
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Do you still have your brake boosters? Obviously check for leaks everywhere. Boosters can leak internally. I assume you used a bottle with a tube that goes into some fluid so air can't be introduced from there when the pedal comes back. Also I assume you didn't over loosen the bleed screw. Pressure bleeders are very nice.
The sequence should be Pass. Front, Driver Front, Pass. Rear, Driver Rear (starting furthest away and going closer to the M/C).
I wouldn't think you'd need to, but as a last resort, you might try fluids designed for a more modern car. The ABS and traction controls require a thinner fluid and I would expect bubbles would be less persistent in a thinner fluid.
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The sequence should be Pass. Front, Driver Front, Pass. Rear, Driver Rear (starting furthest away and going closer to the M/C).
Forgive me but.... Your sequence above is not correct. If you start furthest away from the MC, it would be Pass rear, Driver rear, Pass front, Driver front......yes?
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On the stock TC, the fluid for both circuits goes to the back to the boosters and then to the calipers and wheel cylinders. That means the fronts are actually further from the M/C than the rears.
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I stand (sit) corrected!
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Looking at the convoluted tubing run of the braking system, it's not hard to imagine why getting all of the air out of the system may be a bit difficult. The biggest culprit may be the loop up to the boosters (if you still have them) and back down to the PDWV. Power bleeding may be the way to go. Also make sure that the master cylinder has been bench bled before anything else.
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Ted, I have to sit when corrected. I can't stand that long or that many times! ;D
Joji, that was my assumption, too. I mounted my boosters behind the rear wheel well so my tubing and hose runs are more flat than the stock setup. I didn't have any trouble bleeding mine but I've heard some just have a horrible time.
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The brakes are as original, rebuilt master ,new rear wheel cylinder, stock boosters and front calipers.
The shop manual say to bleed the side closest to the master first front ,then rear then front other side
rear other side.
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Myself, I would either replace, overhaul or remove the nigh on 50 year old boosters.
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Myself, I would either replace, overhaul or remove the nigh on 50 year old boosters.
Me too, except I would just flat out remove them on anything used more often than a show car or museum piece.
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to each his own....
i was extremely happy/satisfied to rebuild and keep the boosters and original braking system intact. excellent braking with little pedal effort.
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Nothing wrong with keeping the boosters as long as they are either overhauled or replaced.
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Where do you find the parts to rebuild the boosters?
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across the pond somewhere in England, or British Isles, or United Kingdom, or Britain, or one of those places! :)
I forget the vendor, but do an internet search for the parts and you'll come up with it.
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Advice in order of preference:
1) Remove the boosters and fit a smaller master cylinder: same pedal effort, slightly longer travel. This greatly simplifies the brake system and makes bleeding a breeze. Moderately easy job for the amateur mechanic. Remember, TC/S came with an un-boosted, SINGLE circuit brake system in the UK so the boosters are not needed.
2) Fit new boosters. Functions identically to the originals but they look different if you are worried about originality. Would recommend professional pressure bleeding if you are inexperienced.
3) Rebuild the old boosters professionally. There are a number of places that do the work. It ain't cheap as most hydraulic cylinders have to be sleeved due to wear. Otherwise same as #2.
4) Rebuild the old boosters yourself: This is just plain DUMB if you are not an experienced mechanic. Would you even know what a worn cylinder looks like? Would you know if they were working properly when you were done? I have 35 years as a mechanic and I have simply stopped rebuilding hydraulics. Sure, most of them turn out well, but most is not all. I want my brake work to be safe, reliable and problem free. That means fitting new hydraulic parts wherever possible.
I have rebuilt several boosters, all successfully but one in particular illustrates my concerns. Someone had previously overhauled the booster and the owner was complaining about poor brake performance. When you pushed on the pedal, it actually moved up, not down! I stripped it and found they had installed a vacuum shuttle valve backwards. It fit both ways so there was no visual indication it was assembled incorrectly. So please do not take door number 4!
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I am in the process of restoring my boosters.
I found a fantastic place in the US - they can provide the entire kit or parts.
Great service and very knowledgeable over the phone.
the company is - Harmon Classic Brakes
www.harmonclassicbrakes.com
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There are several Girling booster rebuild kits listed on ebay and I suspect they were used in other Brit cars so you might also be able to get them at a place like Moss Motors. You can sometimes find complete boosters listed on ebay. Unfortunately, I don't know the exact model booster so you'd have to do a bit of research to find out which one you need.
A last resort would be a restoration shop. White Post Restorations (whitepost.com) seems like for the right money, they could rebuild any brake component. In fact, they sleeve cylinders with with bronze or copper which should greatly enhance the life of them. I've used them and they are good and quick. I'm sure there are others.
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JBC - my TCS has a single circuit set up and a single booster, as it left the factory. The Tamiya model also features one! I've cheated and bought the equivalent Lockheed replacement to fit though.
That could be an option, although the Lockheeds are bigger and the fittings in different places, fit two Lockheeds on the dual circuit cars?
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Bruce, when you finish rebuilding yours, i'll need to get the latest information on where you got the rebuild kits because i'll be doing both my boosters in my new JPS pretty soon.
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Just finished restoring both mine tonight.
Will be fitting them tomorrow.
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Yesterday I removed the brake boosters and made two jumper brake lines.
After bleeding the left side brakes I had a rock hard brake pedal,I took the car for a drive down to Certified Lotus /Glen's.
The brakes worked good but the pedal is way to hard. I'm thinking about replacing the Europa .875 master with the smaller .70 master from a later Spitfire. "Simplify and add lightness" :/beerchug: Glen put some pictures of my car on his page.
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I should have offered you my temporary "jumpers" I made when I did the same thing (while booster were out getting rebuilt). Same experience with rock hard pedal, but high effort needed to stop. Opted to rebuild the boosters and have never looked back...
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Yesterday I removed the brake boosters and made two jumper brake lines.
After bleeding the left side brakes I had a rock hard brake pedal,I took the car for a drive down to Certified Lotus /Glen's.
The brakes worked good but the pedal is way to hard. I'm thinking about replacing the Europa .875 master with the smaller .70 master from a later Spitfire. "Simplify and add lightness" :/beerchug: Glen put some pictures of my car on his page.
I've used the 0.7" master and currently have a 0.75" one fitted which I think gives shorter travel without too much effort. Before swapping cylinders you could try alternative front pads with a better "bite" from cold. I've used both EBC Greenstuff and Mintex 1144; I think overall I prefer the Mintex.
Brian
Edit to add... it's just dawned on me that you're the guy with the red TC and interesting exhaust manifold shown on Certified Lotus's thread. So I'll ask directly - is that a 4-2-1 or 4-1 system ? My interest is that I want to make one and with almost zero experience I'm reading up and looking what others have done.
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4-2-1 The 4 primary are all 17" going into 2 just in front of the shifter u-joint and going into 1 under the starter turning up to the muffler run over the axle along the trans.
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Thank you Bruce, that's very useful info, especially about where the joins are located. I've been playing about with 13" lengths of wire and struggling to get an equal fit within th ebounds of sensible bends so I'll try longer sections today.
Thanks again, it's very helpful.
Brian
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I have a new MC, new servo, new brake lines and had a dry system.
Having filled up the MC, I have fluid both sides of the MC connections, but 50 pumps on the pedal hardly lowers the fluid level in the MC.
I have tried another new MC, no difference.
I have by-passed the new servo, no difference.
If feels like there is no fluid being pushed by the MC or an air lock in the MC, even though I filled up both bores of the MC before fitting it to the chassis.
When I by-passed the servo, fluid did leak from the servo, so I know a little is being pumped.
This is the 6th car I have re-built, and I had no problems with the first 5. 50 pumps on the pedal would have 1/3 emptied the MC, but not this time.
Any suggestions?
I have ordered a reservoir pressurising kit from Machine Mart due late next week. In the meantime, has anyone else had this problem or any ideas on what is wrong, and how to solve it?
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4129R, is this a single or dual circuit system? If dual, could you have tripped the PDWV valve? (And, would that cause this symptom?)
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Single circuit. Very simple system. All new and empty of fluid.
I just wonder if the MC being dry for a long time might not be sealing properly.
But I have tried two new MCs, both bought long ago from Banks. 0.75, single circuit, remote header reservoir. .
Do they have a dry shelf life?
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The only thing I can think of is to suggest that you bench bleed the M/C but I suspect you’ve already done that.
Two other things I might do, although I don’t think it would fix the problem but might give me some insight, would be to use a pressure bleeder and to disconnect the lines at the M/C and see if you can get fluid to pump out and if so, try the same thing further down until you either get to the cylinders or calipers or you find the problem. I’d probably do that as much out of frustration and curiosity as anything. On second thought, I might not use the pressure bleeder because it might mask the problem.
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Bleed the master cylinder first. Remove the brake lines and hold your fingers over the ports. Have your assistant depress the pedal and hold it down. Allow any pressure to release past your fingers. Hold tight and have the assistant release the pedal. Repeat until clear fluid flows out. Reattach lines and bleed as normal.
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I now have a hydraulic pump to pressurise the master cylinder. It took me ages to get it to seal on top of the MC, but I can get the pressure at the top of the MC up to 1 bar (16 PSI).
At last, I have no fluid leaks, but the system loses pressure from 1 bar after a few minutes, yet no fluid comes out anywhere when left pressurised.
I am getting FA at the 4 bleed nipples at each wheel.
I have bypassed the servo.
When pressurised, I release the 1 pipe connection on the single circuit brake MC which goes back to the servo, fluid comes out of that connection and I tighten the 7/16" fitting, but the pedal seems not to be pumping.
I have run out of ideas.
I will have to pressurise the system, and loosen every connection to see if fluid comes out.
Is 16 PSI enough to force fluid though all the empty pipes?
Could all the rubber flexible hoses have blocked up when sitting dry for about 4 years?
The previous 5 cars I have done gave me no such problems. The pedal worked, it pumped easily, and I managed to bleed all 4 nipples without any major problem. Why is this one being so difficult?
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Sorry for my misunderstanding. Here's what I'm not sure of:
Did you bench bleed the M/C?
Having done that, this question is moot, I guess but before you connect any tubing to the M/C, when you push the brake pedal, does fluid come out of the port?
I don't know what you mean by "FA."
Checking my pressure bleeder, it calls for 10 psi so 16psi should be plenty.
You can check for blockages by disconnecting the tube at the M/C and at the cylinders and calipers and blowing air through it. Where does air come out? If you get air at each wheel, do you get more at one than the others? You could connect all but one wheel and try it for each wheel independently. This is assuming no booster in the circuit so you probably have to make adjustments to this strategy (i.e. bypass the booster or test up to it and after it). I doubt the rubber hoses would be blocked just for sitting around but a small critter could have caused you a problem.
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Sorry for my misunderstanding. Here's what I'm not sure of:
Did you bench bleed the M/C?
I have fluid coming out of the port when the reservoir is pressurised and the 7/16" fitting is loosened.
Having done that, this question is moot, I guess but before you connect any tubing to the M/C, when you push the brake pedal, does fluid come out of the port?
No idea, I cannot see
I don't know what you mean by "FA."
"Fuc* All"
Checking my pressure bleeder, it calls for 10 psi so 16psi should be plenty.
You can check for blockages by disconnecting the tube at the M/C and at the cylinders and calipers and blowing air through it. Where does air come out? If you get air at each wheel, do you get more at one than the others? You could connect all but one wheel and try it for each wheel independently. This is assuming no booster in the circuit so you probably have to make adjustments to this strategy (i.e. bypass the booster or test up to it and after it). I doubt the rubber hoses would be blocked just for sitting around but a small critter could have caused you a problem.
Not easy to blow air through the piping. Maybe I will have to make up a connection from my compressor to the hydraulic pipes, but that would blow brake fluid all around my garage, which would be corrosive and mess up the paintwork of all cars in the proximity.
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When you pressurise the master cylinder reservoir by 10-16 PSI, how does the hydraulic fluid pass through the master cylinder so you can bleed the nipples at all 4 wheels?
Well ...........
I have connected another master cylinder and remote reservoir in my bench vice. I have filled the reservoir, and fluid comes out the port straight away. I have then connected a long clear hose to the port via a rubber flexible hose. As I pump the piston, fluid just bubbles up in the reservoir.
Tomorrow I will try sticking my finger over the open port to see if I can get it to pump out of the port, and not up into the reservoir.
I didn't have this problem on the previous 5 cars I bled successfully from dry.
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How do pressure bleeders work? Similarly to vacuum bleeders but backwards!
I'm deconstructing this since I've pretty much just accepted that they work but I think what happens is the piston in the M/C when your foot is off the brake, is behind both the inlet and outlet ports of the M/C. So fluid is pushed from the reservoir into the cylinder and out the outlet port via the air pressure in the bleeder. You could crack open all four bleed screws if you wanted but I just do one at a time. I connect a plastic tube to the bleed screw that goes into a bottle and opens beneath the level of fluid in the bottle. We used to use a soda/pop/cock bottle but you can get nice plastic bottles for the same purpose. Vacuum bleeders work the same way only they suck the fluid from the bleed screws pulling it from the reservoir but they can draw air through the threads of the bleed screw, for example, so I prefer the pressure bleeder.
In the bench bleeding you describe, you directed the fluid from the output port of the M/C to the reservoir but you saw fluid bubbling up in the reservoir that did not come from the tube connected to the output port? I think I misunderstood your description. I don't see how that could happen in a single circuit M/C.
I have used mine several times and it's great! It is a one man operation and should produce fewer bubbles than pump or vacuum bleeding might.
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Did you bench bleed the M/C?
I have fluid coming out of the port when the reservoir is pressurised and the 7/16" fitting is loosened.
Having done that, this question is moot, I guess but before you connect any tubing to the M/C, when you push the brake pedal, does fluid come out of the port?
No idea, I cannot see
Errr . . . hold the bus, please.
1. Either fluid comes out of the port or it doesn't.
2. How do you know if you can't see it?
Or do you mean that you see 'evidence of fluid' when you go look after the fact? – the situation is not clear.
At a guess, I'd say 'evidence of fluid' is not the same as 'fluid flow'. The MC might dribble fluid but won't work if it's 90% full of air.
Follow JB's advice in Reply #30 and you'll quickly identify if a problem exists.
JB is essentially describing a bench bleed performed in the car to save pulling the MC. Perhaps it's time to literally do it on the bench so that you can see the fluid flowing properly from the outlet port.
Tomorrow I will try sticking my finger over the open port to see if I can get it to pump out of the port, and not up into the reservoir.
That's the important part . . and keep the finger in place while the piston retracts.
Good luck.
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https://www.youtube.com/watch?v=7rImn6nJ4Dw&ab_channel=GarageGurus
So having bench bled the MC, how do you stop air entering the system when you disconnect the clear plastic hoses and fittings, and start installing the MC on the car?
Surely the hydraulic fluid will start leaking out as soon as you disconnect the pipes and fittings and let air back into the MC.
Hold the bus, please.
1. Either fluid comes out of the port or it doesn't.
2. How do you know if you can't see it?
As soon as I loosen the 7/16" out port pipe fitting, fluid leaks out of the MC.
In the bench bleeding you describe, you directed the fluid from the output port of the M/C to the reservoir but you saw fluid bubbling up in the reservoir that did not come from the tube connected to the output port? I think I misunderstood your description. I don't see how that could happen in a single circuit M/C.
I have connected to the single out port, a rubber flexible hose, like on the front calipers or where the rear trailing arm pivots on the Y of the chassis, with a clear plastic tube attached to the other end of the hose. All that happens when I push the extension rod in the vice is air bubbles up into the reservoir, and FA comes out of the out port into the rubber hose and clear plastic tube.
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I have this morning bench bled another new MC (as per the video in my post above) so no bubbles come out, then plugged both holes on the bench with 3/8" UNC and 7/16" UNC bolts, fitted the MC to the car, carefully attached the reservoir pipe and the outlet pipe, and tightened everything.
One bleed nipple open, 100 pumps on the pedal, and the fluid level does not go down at all.
I pressurised the system to 16 PSI and it slowly went down to 0 PSI over 3m30s, with the leak coming from the hydraulic pump, as fluid was going from the MC reservoir back into the pump as the pressure decreased.
No fluid leaks anywhere.
Current problems are 1) the MC is not pumping fluid properly (2 different new MC tried, same problem) and 2) nothing comes out of any bleed nipple when the remote reservoir is pressurised to 16 PSI, even though there is fluid in the pipes as I found several leaks in the engine bay when I first pressurised the system.
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Ok, you;'ve bench bleed the master (PS: I just fit rubber plugs to the ports when fitting). Now disconnect the two lines from the master to the boosters at the boosters. Hold you fingers over the lines as someone pumps the brake pedal. Pedal pressure will overcome your fingers but still not allow air in. Do you get flow?
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I have pressurised the system, and systematically loosened the brake pipe unions one at a time, getting fluid coming out of the fittings.
It seems the rubber hoses have become blocked when sitting dry. This car is 4129R, which I drove successfully for about 1000 miles before stripping for a respray.
I replaced one of the hoses to the front caliper, and fluid is now coming out of the caliper bleed nipple when the system is pressurised.
I have ordered all 4 hoses for £28.00 on eBay.
Once all 4 have been replaced, I will address the MC problem again to see what will happen when pumping the pedal and the bleed nipples are actually working with new hoses.
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I have pressurised the system, and systematically loosened the brake pipe unions one at a time, getting fluid coming out of the fittings.
It seems the rubber hoses have become blocked when sitting dry. This car is 4129R, which I drove successfully for about 1000 miles before stripping for a respray.
I replaced one of the hoses to the front caliper, and fluid is now coming out of the caliper bleed nipple when the system is pressurised.
I have ordered all 4 hoses for £28.00 on eBay.
Once all 4 have been replaced, I will address the MC problem again to see what will happen when pumping the pedal and the bleed nipples are actually working with new hoses.
or...the fluid has congealed in the flex hoses from sitting for an indeterminate amount of time. If I may make a suggestion? Before replacing all the rubber hoses...disconnect all of the old ones and bin them. Then FLUSH the remaining metal hoses out with fresh fluid (put bleed hoses on all the frame-mounted nipples and run to jelly jars to catch...). THEN hook up the new flex hoses, reconnect, and bleed. Just a suggestion (yeah, I know the 2 short and 2 rear arm mounted metal pipes aren't included, but they'll be caught up with when you go to bleed the system, since it will be essentially empty after this....)
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The next episode in my master cylinder saga:-
I changed all 4 rubber brake hoses and one wheel cylinder, and now when I pressurise the reservoir tank on the brake master cylinder I can bleed all four corners at the bleed nipples.
BUT.
I disconnected the brake fluid pressuriser, and left a full reservoir of fluid to sort out the master cylinder not pumping properly problem.
I had bench bled the master cylinder, plugged the two holes, and fitted the MC to the car.
When I pumped the brake pedal a few times, the entire contents of the master cylinder remote reservoir emptied themselves over the front spare wheel area. It took much kitchen roll and a wash with soapy water quickly to stop the pristine paintwork on the wings and around the Lotus badge from being damaged.
It is a new MC. I have 2 more new MCs.
Why is the MC pumping back up to the reservoir? You cannot connect the pipes up backwards. The previous 5 cars I have done have all worked quickly using the same plumbing arrangements.
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What master cylinder (brand and application) are you using?
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What master cylinder (brand and application) are you using?
Girling 3/4" bought from Banks. Single circuit. Just the large connection to the remote reservoir and the normal connection to a male brake pipe fitting which takes a 7/16" spanner to undo.
My plan for tomorrow, unless anyone has a better plan, is to bench bleed another brand new MC, fit that, and see what happens.
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Ok, you have a duff cylinder. I did my single circuit set up by bench bleeding the master, and then just pumping through 10 pumps out each bleed nipple. Hard pedal after that and I did it with no assistant. Just saying this to show how straight forward it should be.
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Am I correct in saying you have now tried two new master cylinders. Is it worth going back to the first one now you have sorted your flexi's?
Did you buy them all at the same time from the same supplier? Is it worth contacting them to see if they know of a "bad" batch?
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Ok, you have a duff cylinder. I did my single circuit set up by bench bleeding the master, and then just pumping through 10 pumps out each bleed nipple. Hard pedal after that and I did it with no assistant. Just saying this to show how straight forward it should be.
It was that simple with the last 5 that I have done.
Here is hoping one of my other two will work normally.
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Am I correct in saying you have now tried two new master cylinders. Is it worth going back to the first one now you have sorted your flexi's?
Did you buy them all at the same time from the same supplier? Is it worth contacting them to see if they know of a "bad" batch?
2 from Banks ages ago. 1 from AN other last week.
AN other will be fitted tomorrow.
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SUCCESS !!!
I bench bled a brand new Girling 3/4" MC, plugged both holes, fitted the MC, pressurised the reservoir, and bled the air out from the pipe going into the side of the servo.
I now have a solid brake pedal.
The faults turned out to be:-
4 rubber brake hoses that had closed up, and needed replacing.
1 brake drum wheel cylinder that would not pass fluid through to the bleed nipple.
1 faulty brand new master cylinder that had been sitting around dry for a few years.
Cost of fixing, about £28 for hoses, £12 for wheel cylinder, £30 for a master cylinder and about 4 litres of brake fluid which managed to leak everywhere.
Thanks for your assistance. Discussing a difficult problem with others gets there in the end.
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Great. Glad you are sorted. :beerchug:
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Wow Bruce. You got all your bad luck out of the way.
I am glad you fixed it.
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Congratulations on finding the source of a perplexing problem! :beerchug:
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I have ordered all 4 hoses for £28.00 on eBay.
Did these come with the washers and nuts? The Ebay UK listing I can see selling a set for that price doesn't show them on the image, or mention them in the description.
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No, they did not come with the washers and nuts, and some of the old thin nuts were not re-useable, and the thin star washers are hard to find if lost or not re-useable.
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Thanks
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Thanks
If you use standard thickness nuts, check to make sure the pipe union nut does not hit the thick nut and leave the union loose. If you just use 1 star washer on the nut side of the hose, there is just about enough clearance for the pipe union to be tight. If not, grind a bit off the thick nut, and run a bolt through it to make sure the thread is clear, as fitting the nut to the hose with a jammed thread wastes a lot of time and more spanner rash.
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Half nuts are readily available at industrial suppliers. It's 3/8x24NF thread. Same with anti-vibration lock washers.
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I am just about to start filling #7 Europa with brake fluid, and start bleeding the system.
I put the new M/C in the vice, connected tubes to the in and out, filled the remote with fluid, did 3 pumps and the remote reservoir started bubbling, and fluid leaked out all along the push rod.
It seems either they were from a bad batch, or they don't like sitting around dry for a long time.
New M/C on order from eBay.
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New M/C arrived quicker than expected.
Bench bled easily.
New rubber brake hoses and drum wheel cylinders.
I pressurised the remote reservoir and bled all 4 bleed nipples in under 10 minutes on my own.
Success. I wish the previous 6 had been so easy.
The only thing that took time was getting the M/C extension rod the right length so all 3 pedals were in line. I had to use an old extension as the new ones did not leave enough thread at the joints.
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:beerchug: :pirate: