Lotus Europa Forums > Technical Articles and DIY tools and tips
Yet another Tandem Master Cylinder installation
EuropaTC:
Ok, yet another tale of someone installing a non-OEM master cylinder in their Europa. This probably won't be of great interest to you guys on the left of the pond, but for anyone with a UK or European car it might be of help. So here goes.
The standard system consists of a single circuit m/cyl of 0.7" bore with servo assistance. I replaced the m/cyl with a 0.75" one several years ago and thus had a slightly higher pedal pressure with less travel. The single servo is located in the engine bay & brake pipes convey fluid from the front to rear servo & then back again for the front brakes.
The plan is to replace the single circuit m/cyl with a tandem m/cyl at 0.7" bore, to remove the servo assistance and replace the front pads with Greenstuff pads in the hope that this alleviates the lack of servo assistance. If pedal pressures are unacceptable then to re-install the original & a second servo unit as per the US spec Europa Specials.
The OEM m/cyl as used on the Export Spec Europas is now very difficult to source and appears to be only available via specialists at appropriately high prices. (£180 seems to be the going rate if you can find one). However there are more affordable options available if you are prepared to do some modifications and as such I purchased a tandem m/cyl intended for the Triumph Spitfire 1500, part GMC226 for approximately £75. This has the same bore and flange pattern as the existing single circuit m/cyl although the actuating rod will need to be swapped over for the Lotus one.
Image01
However this will not be a straightforward installation. Firstly the reservoir is a push-fit & sloping wedge-shaped item because the m/cyl is mounted at an angle on the Triumph bulkhead. This isn't a big deal because the Europa needs a remote system anyway whatever cylinder is used.
The second problem is that the brake pipes exit on the LHS of the cylinder. On a LHD car this isn't an issue as they exit towards the wheel arch where there will be plenty of room, but with RHD I found that the secondary circuit pipe was a very tight fit against the fibreglass floor of the front compartment.
I decided to modify the bodywork underneath the radiator to give more access for the front brake pipe outlet. Although not essential, this will make installation and maintenance easier in the future and there will be no significant impact on the radiator mounting or front boot space.
Image02
So a small cut-out was made as shown in the photograph, using a combination of dremel & hacksaw blades from either above or below. A repair section was moulded by the simple process of making a cardboard template, lining this with tin-foil & then laying up 2/3 layers of matting. I removed this from the mould in a plastic state which allowed me to offer it up to the hole & trim where necessary using a pair of scissors - much easier than when the resin has full hardened !
Image03
Then it's simply bonded into place as shown in the photographs, finished off with surface tissue, left overnight & then given a coat of matt black paint to tidy it up. It's not the world's neatest job but it looks on a par with the rest of the boot interior and is certainly fit for purpose.
Right, the next stage is to remove the OEM part & bolt in the new one. As can be seen from the next picture, the actuating rods need to be changed over, or at least the Tandem push rod needs modifying & threading to accept the Lotus extension. I decided against modification because the diameter of the new one is slightly less than the OEM rod and hence the resultant thread didn't look strong enough to me for a critical item.
Image04
New m/Cyl modified and it's installation time, a simple bolt in job.
Points to note - the new cylinder has metric threaded fittings for the brake unions so you'll need some modern couplings. I used new brake pipes rather than modify the old ones, the cost is minimal and although it takes more time, it's much easier to work with new materials than old. The primary circuit goes to the front brakes, the secondary to the rear brakes on a front/rear split.
Image05
The reservoir now needs to be remote, and as with the OEM installation, it is all very close to the steering rack bellows. I used 90deg plastic elbows coming out of the first chamber and a straight connector for the second (forward) chamber. In truth the new installation is fractionally lower than the OEM m/cyl & brake pipe but I still decided to fabricate a small aluminium cover, as shown in the photograph, to isolate the rack bellows and the filler pipework.
Image06
The two filler pipes go through the original hole into the front boot with the new 2 chamber reservoir mounted on a new bracket in the same place as the OEM single reservoir. I might change this at some point to include a low level switch, but for now it's acceptable. (You can also see the yellow dust and overspray from last summer’s respray still hanging on in the radiator, fan and other places you don’t normally see from the driving seat ! )
Well, how different is in practice with no servo and a smaller m/cyl bore ? Hmm, now this is a strange one. I know the servo was working properly and as expected the reversion to a 0.7" bore has restored the pedal travel to it's original design, but the overall impression is that removing the servo has had very little impact on the braking performance in terms of pedal pressure. It's still very easy to lock the front wheels with a deliberate stab to the brake pedal, and if you brake normally with a gradual increase in pressure then basically there's nothing to choose between the systems in terms of usability.
Edit to add:
PDF file with the pictures inline with the relevant text, plus an update from 2016. The same m/cyl but with different pads (Mintex M1144) and pedal leverage ratios.
LotusJoe:
Nice documented modification. :trophy:
3929R:
Nicely done. Thanks for posting the write up.
--- Quote from: EuropaTC on Sunday,September 23, 2012, 03:48:08 AM ---Well, how different is in practice with no servo and a smaller m/cyl bore ? Hmm, now this is a strange one. I know the servo was working properly and as expected the reversion to a 0.7" bore has restored the pedal travel to it's original design, but the overall impression is that removing the servo has had very little impact on the braking performance in terms of pedal pressure. It's still very easy to lock the front wheels with a deliberate stab to the brake pedal, and if you brake normally with a gradual increase in pressure then basically there's nothing to choose between the systems in terms of usability.
--- End quote ---
I never got to drive my car when it had servos. I am happy to hear another testimony that I'm not missing anything.
EuropaTC:
Hi, thanks for the comments guys.
Incidentally I don't want to give the impression that the servo doesn't do anything at all, just that there are other options available. I think if you want to remove a servo you need to look at pad materials because the OEM spec was for a harder pad if a servo was fitted. The EBC Greenstuff pads I've fitted are known to have a good "bite" on non-servoed systems although over here folks use them on both.
Brian
YellowS4DHC:
Europa TC,
Your write up was very, very helpful to me - and timely too.
I just acquired a Federal TC that, for some reason, didn't have a tandem M/C; the PO modified it back to a single M/C configuration and without the servo.
After reading your article, I bought and installed the Spitfire M/C and replaced all the front bundy lines. All very easy since my car is LHD. You even forewarned me about the metric fittings on the M/C. I got motivated and went on to rebuild both calipers (pistons were crap). All I need now are some EBC pads.
Thanks for taking the time to document and post your work, you made life easier.
Rick
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