Brake servo

[JNS]

I have a failed Brake Servo in my 1971 Europa twin cam. Does anyone know if these were used in any other cars, (Herald or Spifire perhaps)? It may help me source a replacement.
Thanks
Jeff

[BDA]

I believe that the Girling boosters were used on several other cars but unfortunately, I can't find a cross reference right away. I did find this place over on your side of the pond: Powertrack Ltd. http://www.powertrackbrakes.co.uk/brakes.html. Also Europa Engineering sells a replacement: https://www.lotus-supplies.com/part-category/brakes/page/9/. If you're adventurous, you should be able to get rebuild kits from a Girling parts supplier. It looks like Rimmer Bros. might be able to help you (https://rimmerbros.com/ItemSearch--search-Brake-Servo-Repair-Kit--srcin-1).

Good luck!

[jbcollier]

The Girling booster is no longer available and major parts are not available.  Rebuild kits are available but, by now, cylinders are worn.  You can have the cylinders sleeved and then new kits fitted.

A better repair for a car meant to be driven would be to replace the old boosters with new Lockheed ones, which are available.  They can be supplied with a bracket that allows them to bolt straight in.

My preference would be to remove the boosters entirely and get rid of seemingly miles of excess plumbing and make the brakes a doodle to bleed.  You simply need to fit an 0.70 master cylinder.

Brake cylinders wear.  You can’t simply fit new rubber seals. If you check the maintenance schedule, all brake cylinders were meant to be replaced every 40k miles.  You can overhaul front calipers effectively as new pistons are available.  Rear wheel cylinders should simply be replaced as they are inexpensive and widely available.  After years of working as a mechanic, I now only fit new master cylinders.  I have seen too many failed “rebuilt” ones.  That includes ones with sleeved cylinders as well.  I’m not saying it can’t be done well, just that it often isn’t.

Took me years to recover from my first experience of a brake pedal going uselessly to the floor.

[EuropaTC]

With respect John, it was the rubber parts of the braking system that were to be automatically renewed, not the actual master cylinders - they were supposed to be checked for wear and overhauled if within spec.  But what always comes as a surprise is that it actually said  "40,000 miles or 3 years, whichever comes first" and that overhaul includes replacing hoses, etc.  Anything rubber was to be replaced and even the filter in the brake servo was also replaced at a service.    I wonder how many times that actually happened ?

But having said that I do agree with your principle given the age of all these cars. 

Rear cylinders are so cheap it's not worth even a hobbyist's time to repair. As for the master cylinders,  new parts are available for the single circuit brakes and alternatives are known for dual circuits. So there's no need to compromise on a safety issue, you can easily get the brakes as good as they were when the car was new.

Brian

[JNS]

Good information. Thank you everyone.
It does raise a further query. If I removed the servo and ran the car without it, what would be the effect on the brakes and how would they feel? Is it legal to do this?
I would welcome any thoughts.
Jeff

[BERNIEHUMBER]

HI:I have ,in the past, taken off a servo and ran with an oversized MC and it worked fine.
How legal it was depends if you have an accident and how diligent the insurance appraiser is.
Have a look at this:

https://www.youtube.com/watch?v=quRJ4_sqMYU

The fellow does a rebuild on a Tiger servo and you an get an idea of easy/hard it is to do.
I rebuilt(after checking the bores for scoring etc) my Tiger servo 3 years ago without incident.
The rebuild kits are on Ebay from the UK.
Good luck on either path.

[jbcollier]

If you take the boosters out, you need to switch to a SMALLER master cylinder.  For the Europa, generally a 0.70 master works best.  Some people have kept the 0.75 master and are fine with the harder pedal.  It's about the same as a typical race car.  The extra pedal pressure required has the benefit of making threshold braking easier to achieve.  That said, I run an 0.70 and am very happy with the pedal pressure and find the brakes easy to modulate.

Instead of fitting a smaller master, you can drill another hole in your brake pedal closer to the pivot point.  This has the same effect as fitting a smaller master.  The disadvantage is that now the brake pushrod is working at an angle and a side load is being applied to the master.  This will reduce the life of the master cylinder.  How much is hard to say.  The Europa brake pedal is relatively far from the master so the angle of offset is reduced quite a bit.  When I first heard of someone doing this, I thought they were crazy.  Now, after a lot of mulling over, I think it is an OK, albeit not ideal, solution.

Introducing a fault into the brake system would be a legal issue.  Minor modifications that do not impair their function is not a problem.  The boosters on Europas are not that powerful.  The difference between running with or without is noticeable but not debilitating.  Take the typical 70s US car and that's another matter entirely.  The brakes go from being best operated by your big toe to both feet stomping as hard as you can.

[surfguitar58]

If you take the boosters out, you need to switch to a SMALLER master cylinder.  For the Europa, generally a 0.70 master works best.  Some people have kept the 0.75 master and are fine with the harder pedal.  It's about the same as a typical race car.  The extra pedal pressure required has the benefit of making threshold braking easier to achieve.  That said, I run an 0.70 and am very happy with the pedal pressure and find the brakes easy to modulate.

Instead of fitting a smaller master, you can drill another hole in your brake pedal closer to the pivot point.  This has the same effect as fitting a smaller master.  The disadvantage is that now the brake pushrod is working at an angle and a side load is being applied to the master.  This will reduce the life of the master cylinder.  How much is hard to say.  The Europa brake pedal is relatively far from the master so the angle of offset is reduced quite a bit.  When I first heard of someone doing this, I thought they were crazy.  Now, after a lot of mulling over, I think it is an OK, albeit not ideal, solution.

I've posted this before, but regarding the new-hole-in-the-pedal approach, the off-axis pushrod problem can be solved by putting a block under the pedal assembly. My pedal bolts have an extra 3/8" sticking out past the nut, so raising the whole pedal assembly by 1/4" and drilling a new hole 3/8" closer to the pivot for the pushrod clevis would keep things pretty much in line and have about the same effect as going to a .70" MC.

At present I am driving around without boosters and with the stock .875" master cylinder and an un-modified pedal assembly. I am totally used to having to stab the pedal with authority at this point, and I really like the short throw of the brake pedal. It does take some getting used to after driving the family car with power brakes.

Tom

[EuropaTC]

Good information. Thank you everyone.
It does raise a further query. If I removed the servo and ran the car without it, what would be the effect on the brakes and how would they feel? Is it legal to do this?
I would welcome any thoughts.
Jeff

Hi Jeff,
From your location I'm guessing you have a UK spec car with a single circuit brake system ?  If so, you may already have the 0.7" master cylinder, I'm pretty sure the original one on my TC was 0.7" and I've certainly run the car with that size and a brake servo. 

If yours is the same then removing the servo is no big deal. Fit Greenstuff front pads and after a couple of miles you'll wonder why the servo was there in the first place.

I ran my TC with the OEM discs/Drums with a 0.7" cylinder/no servo  and then changed it to a 0.75" m/cyl when I wanted to try a lower pedal travel. Yep, slightly higher pressure to get used to, you might like it, you might not - it's just a personal preference thing.

I'm currently running with a 0.75"  (19mm actually) m/cyl, discs all round and no servo.  Mintex front pads, EBC Ultimax2 rear pads & braking is very much like a modern car.

Brian

As for legality, what matters is that the brakes work, not that they are as originally designed.

[BERNIEHUMBER]

HI:
My changing the MC because of uninstalling the servo was with a Healey.
It went .75 to 7/8 and yes pedal press went up but it all went well.
The thing that worries me about my S2 is the single circuit brake system.
If I get more motivated that is something I wanted to improve upon.

[jbcollier]

I have worked a lot with both single and dual circuit brakes.  Generally there is more to go wrong in a dual circuit system and, so, more does go wrong.  The key point of failure with both systems is weeping fluid out until the brakes disappear.  Most common leak points are drum brake wheel cylinders and the master cylinder itself.  Both these issues are readily controlled by regular maintenance and the addition of a brake fluid level warning light.  Regular maintenance means fitting new wheel cylinders, brake hoses and a master cylinder every 40K, changing the brake fluid every 2 years and weekly level checks.

I am not arguing against dual circuit brake systems.  Just pointing out that there is nothing wrong with single circuit systems.  Do fit a brake fluid level warning light!

Other random thoughts:

- single systems are a breeze to bleed

- VW never had problems with bypassing masters until they went to a dual system.  The master worked great until it didn't whereupon it went straight to the floor, dual circuits be damned.

[Clifton]

Someone posted on here about making a dual tandem set up. If they make it, a 5/8 front feels perfect, I have a .75 rear. A little firmer than a regular car. I can't imaging stopping at 75 + mph with a .75 MC. It must feel like you are towing a trailer. Old Honda SOHC bikes are like this. Too large a master. No feel and don't stop. A smaller MC swap makes them feel better too.

[JNS]

Thanks again everyone.
I do have a 0.70 girling master cylinder so perhaps I may try it without the Servo. and invest in some of those brake pads.
Cheers
Jeff