Dual-circuit brake master cylinder

[mct340]

So it turns out that CP4627-2PRM100 is not a suitable replacement.
Because Caterham mounts the part with the push rod facing forward, the brake lines attach to the wrong side when it is turned the other way for the Elan. There is not enough room for the lines to clear the inner fender (left hand drive cars). It would probably be fine for right handers.
I now have a lovely AP master cylinder for sale which would suit all who drive on the wrong side of the road or own a Caterham 7.
What a PITA. (':x')

[twincamman]

you will have to cut a hole in the fender well any way ---even with the small masters used on my car so -----get the sawsall out and bite the bullet ---make a nice little plate to cover the hole and keep the cats out ----ed

[steveww]

I would be interested to know what front callipers you end up using.

I have seen on a Triumph Spitfire racer the Caterham big brake set up. I think this may be over kill on a light car like the Elan and may give too much bias to the front.

[TomR]

I checked with Pat at Kelvendon and he thought he would have a LHD pedal box ready by spring with luck.

Tom

[cabc26b]

Sorry about that, drawing sent should have made that clear.

If your constraint is you can't, won't cut pedal-box or inside fender well then you have very limited options - as ed has mentioned, the dual master will require a blister on the fender-well . I have formed pretty tight radius with hard lines in the past you are looking minimal protrusion ( 3/4 to 1 inch ?) get a silly putty egg and make a mold. or get the girling dual master.

[mct340]

Here's some photos replacing the Girling Tandem master cylinder with the AP version. When I get it plumbed in I'll report on the pedal response. I hated to cut that hole because I have tire clearance issues on full lock. I'm running very wide autocross A6's so it shouldn't be a problem for stock cars.

[twincamman]

could you not have the master rebuilt????? I could not find a replacement for my Caterham master [it was used on 1984 1/2 mgbs for 6 months ] so I had it rebuilt --are you interested in selling the old one ???? here is a close up pic of the set up on mine -and the RHD Caterham set up ----your masters you bought are used on S2 Europa's also--I have 205 x 13 tires on my elan so you may be OK for FULL lock clearance -as I said earlier 'its a pisspot full of work and cost 'you may be better to add an adjustable bias system with the knob mounted on the dash useing the new master and cut your losses ---it works as well for your application --ed

[jkolb]

I reinforced the fiberglass with carbon fiber cloth, wet laid in epoxy. By laying it up on the top, side, and the firewall it created a very rigid structure with no flex.

Jerry

[twincamman]

I had intended to re enforce my foot box using aluminium at the engine rebuild but didnt - --next time Ill do it - -ed

[cabc26b]

I thought I would revive this post ( and the other on tandems) For what its worth I found alternatives to the AP cylinder , for a few reasons , soem mentioend here and else where -

There are two master cylinders that I have sourced and modified that look promising. Both are .75 inch Alloy tandems , one made by Nabco ( for the Datsun F10) RHD folks should not have to work as hard as I did. the other is by raybestos Both a VW and a Datsun application . The Nabco is modified for the a LHD Elan by switching the outlet port. The raybestos was modified by switching it to remote reservoirs ( using tilton parts) and turning down some extra material next to the flange to make it fit better. The banjos are Aeroquip.

George

[jkolb]

I modified my pedal box (LHD) to accommodate a balance bar. Wasn't too difficult, but I had the welding done by a professional (TIG). It was necessary to relieve the inner fender and build a little fiberglas pocket. Biggest problem is the balance adjustment. I purchased a remote adjustment, but had to modify the clutch cylinder actuating crank to clear the adjuster. US vintage also doesn't allow the adjustment to be made while racing so I had to locate it where I could not reach it - stupid rule! I used Girling master cylinders with remote reservoirs. Ordered them from Burtons in the UK and they were cheaper than US suppliers even with freight.

I will try to take some photos.

Jerry

[patrics]

Hi,

Just a quick comment about the problems with the master cylinder port entry side on left hand drive cars.
Is there enough clearance to run aeroquip type hose with a couple of banjos directly from the master cylinder down to the three way or directly to the calipers?

If there is enough clearance this is what I would do.

Regards
Steve

[cabc26b]

Hi Steve,

To answer your question, not really .

on the ones that I have held in my hands the outlet casting for the rear circuit fouls the fenderwell before you even get it seated. That is why we machined and plugged the forward LHS port on the Nabco and relocated it.

George

( the bottom port unit was a cleaner install and this will use banjo to make the first 90 degree right hand turn)

[patrics]

Thanks George,

I didn?t appreciate that the brake master cylinder was against the inner wing on left hand drive cars.

Could the pedal box be redesigned to put the brake master cylinder back to centre position?

Doesn?t matter for your self as you have already made a lot of effort to sort the master cylinder.

Cheers
Steve

[cabc26b]

Hi Steve

You are correct in that the pedel box could be re-worked. The decision I took was based on the following - the master cylinder was easier to modify than the pedal box. Second on this build I am being very careful not to take the car too far away from stock - If one wanted the exact oem specification they will be able to remove the master replace with a the 5/8 single circuit set up with little fuss and there would be no evidence left behind that the other config was used ( no cut fender well or fire wall)

Picture to illustrate