Dual-circuit brake master cylinder

[mct340]

I'd like to get rid of the original dual-circuit, single piston brake master cylinder on my autocross S4.
Is anyone producing a suitable balance bar, dual master setup that works with the stock pedal?
Thanks in advance,
Mike

[twincamman]

they are available from speed shop and race shops but a huge job to install-they fit in the front ENGINE compartment --why not just hook up an adjustable valve hydraulic bias system to your existing system??ed

[mct340]

Yeah Ed, I've got a reducer valve on the rear circuit but I was hoping someone would have a better system worked out by now. It's getting to the point where there's not much that hasn't been solved.
Cheers,
Mike

[rgh0]

Dual pedal box photo I got some time ago. Cant remember from where I got the photo.

Clearance on the brake cylinder side in the engine bay is a problem also I think and requires some fibreglass modes to the wheel well at least in rh drive cars.

26R's had a dual balance bar system I believe but I dont have any photos of one. Its one 26R part that TTR does not make

cheers
Rohan

[twincamman]

the pics of mine are too many pixels ---email me ill send a pic of mine ----lot of fabrication though - there was another thread on this a while ago ---try brake bias system or check my other posts by twincamman -----ed ----ed

[twincamman]

Ok Mike----most of them have been ---mine has a dual master system and clutch master from the components factory in 1964 --you need a set of front AR brake calipers - -- very costly----and the brake pucks only come in racing compounds so you have to constantly ride them on the street to keep the temperature up ---------- and a rear disc brake set up -[ very similar to an early Jag rear system ]-[Im told by the Dave bean people the rear calipers are unobtainable ] but you may find some ----its a lot of fabrication and cost unless your racing ----and I don't mean vintage --OR GYMKANA --its hardly worth it for the street but email me and Ill send a pic ----- were dealing with with brakes and safety and liability here --------the pic shown in the thread relies on the fiberglass in the foot well for support of the masters ---not a great set up as there is a lot of pressure exerted on the master cylinder mounting through bolts and transmitted to the fiberglass and eventually its going to fail under a hard brake situation ---- a potentially very embarrassing situation ------------ -----ed

[batfish]

Mike

Pat Thomas at kelvedon sells the peddle box. It is a long job to fit requiring modification to the inner wheel arch and steering column, different length push rods etc .

http://www.kelsport.net/parts/product_d ... ectionID=2

Regards
Andy

[cabc26b]

Hi Mike,

I spoent some time looking into this also so , some things I picked up along the way.

If you have a LHD car then the RHD pedal boxes will have to be cut on to make work, I did not feel good about doing this and so never bought one. However, In my last correspondence with Pat he mentioned that he was looking at making a LHD version so that may be an option in the future.

I looked into the stock pedal route and found a company that developed this for another application and asked for drawing to see if would work, they never got back ( they are a vintage racing brake outfit and also a AR racing distributor out of the UK) if you want I can look them up for you.

I have not had a fiberglass failure yet on an elan so not sure I would spend too much time on that worry, if this was a problem then the regulators make/model notes would have flagged it.

Brake calipers - AR's in the front and 10-8 stock rears are a common set up in vintage .I don't know too many people who wish for more rear brake. Once you get close to a two-inch piston locking the rears will be the problem - That said there is kit out there that will allow you to use a AR/NR set up. but as noted this is very expensive and the AR/NR are kind of antique 50's stuff with limited pad availability - but they will haul a light car down like an elan with no problem.

On my latest project I will be using a AR racing tandem master with a proportioning valve on the rears. I will be ditching the cast iron calipers for alloy but will not be using the AR/NR set up. I want better pad options as this car will be on the street and the track. I am looking to add some lightness in the corners - so wlll also use alloy brackets and hubs up front.
I will be using calipers that have better pad choices that the AR's.

Last thing - There are people out there who are successfully running an elan on track with out a dual master set up - so I think it can be done. I never got the brakes on my elan to work like my Sports racer of formula car so that should not be the objective, but they did work better than a lot of other cars out there on track.


Good luck with the project

George

[Frank Howard]

Andy,

Nice car! I see you have installed insulation where the headers will go. Do yourself a favor. Add more insulation right below the existing insulation on the chassis. That is where you will feel the heat at your feet. Much easier to add it now than later.

[twincamman]

George ---the foot well on my car needed extensive strengthening --there were actual cracks at the front of the foot well ---and no sign of other crash damage --and still has a slight movement of the foot well under a hard push ------I strengthened it with 4 oz glass [ a nasty job] ---ed

[cabc26b]

Hi Ed, I must be lucky . I have had 5 early cars. 3 of them "in period" race cars and have fortunately not had issues with the footwell/pedal box area deteriorating. Would be intrested to know what you think caused the failure the was your car cut up to install the dual master ? Fluids soften the glass ? I have seen some older fiberglass get spongy ( early polyesters had the reputation of being hydophilic) was the car well cared for ?

[twincamman]

it spent 30 years abandoned in a barn dissasembled --this is how it arrived --well kept??????I don theen so -Lucy ----- --ed

[mct340]

George,
Do you have a website for the master cyl you intend to use?
Mike

[cabc26b]

Mike,

This is a current product from AP racing . I think they have the mechanical drawing online with there other product/parts - look for CP4627 - if you can't find it PM me and I will see about getting you the PDF of the drawing .

G

[mct340]

The AP Racing part no. for a suitable replacement tandem master cyl. is
CP4627-2PRM100.
It is sold only to Caterham Cars who must be contacted directly.
Thanks to George and Garrett.