Lotus Elan

Dual-circuit brake master cylinder

PostPost by: mct340 » Fri Jan 23, 2009 6:54 am

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')
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PostPost by: twincamman » Fri Jan 23, 2009 11:38 am

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
Last edited by twincamman on Sun Mar 01, 2009 1:28 am, edited 1 time in total.
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PostPost by: steveww » Mon Jan 26, 2009 11:28 am

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.
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PostPost by: TomR » Wed Jan 28, 2009 10:55 pm

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

Tom
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PostPost by: cabc26b » Fri Jan 30, 2009 2:17 pm

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.
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PostPost by: mct340 » Sun Mar 01, 2009 12:34 am

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.
Attachments
SANY0048.JPG and
swap the push rods (AP warns against this but Colin wouldn't have listened either)
SANY0047.JPG and
cut a hole like Ed suggested
SANY0045.JPG and
the AP part is longer and has ports on the wrong side. it will stick out about 1''
SANY0034.JPG and
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PostPost by: twincamman » Sun Mar 01, 2009 12:46 am

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
Attachments
P1010074-1.JPG
P1010074-1.JPG (22.68 KiB) Viewed 5323 times
P1010045.JPG
P1010045.JPG (23.72 KiB) Viewed 5488 times
P1010078.JPG and
Last edited by twincamman on Tue Mar 03, 2009 10:54 pm, edited 1 time in total.
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PostPost by: jkolb » Tue Mar 03, 2009 12:09 am

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.

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PostPost by: twincamman » Tue Mar 03, 2009 3:22 am

I had intended to re enforce my foot box using aluminium at the engine rebuild but didnt - :? --next time Ill do it - :) -ed
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PostPost by: cabc26b » Wed Sep 23, 2009 10:06 pm

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
Attachments
tandem3.jpg and
Nabco on the left a little shorter. rear outlet was shaved off and plugged. Raybestos has downward firing outlets.
Tandem2.jpg and
look see at the fittings. the raybestos will require a little clearance/notch made for the hard line to mate to the rear circuit.
Tandem1.jpg and
side by side , the nabco should be pretty easy to work for a RHD car
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PostPost by: jkolb » Sat Sep 26, 2009 4:49 pm

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.

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PostPost by: patrics » Tue Oct 06, 2009 7:24 pm

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
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PostPost by: cabc26b » Wed Oct 07, 2009 12:56 pm

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)
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PostPost by: patrics » Thu Oct 08, 2009 7:19 pm

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
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PostPost by: cabc26b » Thu Oct 08, 2009 9:05 pm

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
Attachments
MasterCyl.JPG and
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