Brake Master Cylinder Question for TOPTON

[Lean Machine]

Tony. I believe your brake master cylinder has two remote reservoirs for the front and back, modified similar to mine. I have noticed recently that the reservoir for the front brakes decreases and the reservoir for the back brake increases and every so often I have to transfer fluid manually from one to the other. Have you experienced such a problem? or am I developing a master cylinder defect? originally the the front and back reservoirs would have been combined so the fluid would transfer from one to the other being in the same pot. What is the solution? change the master cylinder or revert back to the old system by bolting on a single, twin chamber reservoir onto the master cylinder? Does anyone else have any ideas or have had such an experience? how weird? Any solutions, ideas most welcome.

Tony TCB.

[wild rover]

I would go with the master cylinder problem. Consider a replacement the kits have never been that succesfull.Best of luck

[Campbell]

Sounds like a master cylinder problem to me.

Cambelt

[TOPTON]

I haven't had that problem at all. But I would agreee with the above 2 comments. It sounds like the seals on the piston in the master cylinder is allowing the fluid to move backwards instead of forwards. I would also guess that the rear brakes aren't working as good as they should because of it.

[Lean Machine]

Thanks for the replies guys. The brakes are working fine and the efficiency of all four brakes were very good when the guy checked them at the MOT recently, and there are no leaks anywhere. Somehow, the fluid in the master cylinder is finding its way back into the opposite reservoir. Although the problem is very slight and takes a long time for this to happen, there must be something wrong inside with the master cylinder seals, but the thing that made me wonder is why originally both reservoirs would have been combined as one unit. I thought maybe, they did this to overcome such a problem, should it occur as the fluid would level out in the combined reservoir. This is why I wanted to know if TOPTON had ever had a similar problem as his reservoirs I believe are also separate remote ones. Well, he says not, so I must assume that mine has a problem. It will be going back into the classic car garage soon for the steering column uni joints, so I'll get the guy to fix the master cylinder at the same time, but what I might do is revert back to the old system of a combined master cylinder as I honestly can't see the benefit of remote individual reservoirs.

PS. there is also a Bias brake tap in the cabin which I have never touched as it was set by the previous owner. What does this do exactly? Could that be contributing to the problem? I always thought this was to isolate the rear brakes for track use. Is your car fitted with one of these Tony? Maybe I'll get rid of that at the same time of repairing the master cylinder as I don't use it anyway.

Tony. TCB.

[PoleDriver]

I've actually just thrown away an old one of these master cylinders! It looks like the fluid will transfer from one reservoir to the other when you lift your foot off the pedal, hence the braking efficiency still being good.

This is just an observation... It looks right, but I may be wrong!

[Lean Machine]

Got the car back from the mechanic today. He checked the braking system and the two reservoirs. The brakes are all working efficiently and there are no leaks, but the fluid transfers from one reservoir to the other over time. Consequently, he says changing the master cylinder is not justified. Instead he will link up the two reservoirs via a T piece to solve the fluid levelling problem. We are waiting for the part and it will be installed on the next booking, soon.

Tony. TCB.

[lear]

Interested in this topic as I was just this weekend thinking about how to move to a two cylinder system to enable fitment of a balance bar and bias adjuster in the cabin. Do you still have the servo fitted in your twin cylinder set-up or does the pedal operate directly on the balance bar to which, presumably, the bias adjuster is connected? The reason for the bias adjuster in the cabin is to move the brake force distribution whilst on track. I have 300mm discs and race pads on the front and am planning to upgrade the front calipers but will need the bias adjuster to offset potentially being overbraked at the front. Very grateful for any pics of your installation!

[lear]

Sorry, just saw you mentioned a bias tap which suggests it is plumbed into the brake pipe as opposed to turning a balance bar

[Lean Machine]

Hi Lear. The braking set up was done by the previous owner, presumably because he upgraded the braking and used the car on the track occasionally. The following is what I can see has been done.

. Twin remote brake reservoirs
. Bias tap in cabin in line with brake pipe leading to rear wheels.
. Original bias under bonnet disconnected.
. After market servo (smaller in diameter)
. 4 pot calipers.
. Larger discs.

If I get the car out at the week end, whether permitting, I'll take some photos and post them for you to see. I am no expert on brakes, but you will probably make more sense of what the previous owner did. I'll say one thing though. The brakes work very efficiently, because this is my third V8 wedge and by far the one with the best brakes.

Tony. TCB.

[adam quantrill]

Another advantage of twin reservoirs - it occurred to me - is of a brake overheats and boils, and the reservoir spills over, at least you have another circuit with brake fluid in it.

[lear]

Thanks Tony - I think I can now picture how it works!
Lear