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Brake fluid seeping


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Brake fluid appears to be seeping out from the master cylinder cap. Fortunately it is silicone fluid so no paint damage but the body of the cylinder is damp. Going to try another cap & a new rubber seal inside the cap. Is this likely to cure it or anybody have any other ideas. Have heard some people have used PTFE tape on the threads but when that gets saturated with fluid it becomes a mess. Is it perhaps the poor quality of the cap/thread?

Cheers.

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Hello Monty, I have a theory, if we fill the cylinder too full the fluid expands as the brakes heat as we flog our cars around the country lanes, I, like you have the same problem. I put a few squares of toilet paper under the cylinders to catch the offending liquid. I have tried reducing the amount of fluid and it still happens. Happy for my theory to be disproved, cheers, Andrew

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Hi

 

It's as Andrew describes above, but squirting out the air bleed hole in the top (where the bump in the centre is) - if you don't have this type, the fluid finds it way round the threads of the cap. Either way it's a combination of expansion and sloshing about.

 

The only answer with normal fluid is to use a stainless catch tray and as you say regularly mop it up. Alternatively use something like Castrol SRF which tends to expand less and resists boiling to a much greater degree.

 

Regards

 

Tony

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Hi

It's as Andrew describes above, but squirting out the air bleed hole in the top (where the bump in the centre is) - if you don't have this type, the fluid finds it way round the threads of the cap. Either way it's a combination of expansion and sloshing about.

The only answer with normal fluid is to use a stainless catch tray and as you say regularly mop it up. Alternatively use something like Castrol SRF which tends to expand less and resists boiling to a much greater degree.

Regards

Tony

Thanks Andrew & Tony. Yes, I did wonder if that was the problem, the same as you guys. I also have another TR4 & the cap on that one seems fine although I do recall a similar scenario with that one a couple of years ago. On the car in question the cap does seem to be a poor fit so have ordered another cap & seal to see if that is better. A racing guy recommended putting a sports type sweatband around the body of the master cylinder to help soak up any residue of fluid. It does work but the band does need a rinse out every so often!

Incidentally Tony, what is the correct level of fluid in the cylinder to keep the brakes ok & to perhaps help with this boiling over or spillage?

Cheers.

 

Cheers.

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Monty

 

The PO fitted some self adhesive terry toweling around the top of the master cylinder on my car to catch any overflow

 

Looks a bit naf but seemed to work

 

Graze

Edited by Graze
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Monty

The PO fitted some self adhesive terry toweling around the top of the master cylinder on my car to catch any overflow

Looks a bit naf but seemed to work

Graze

My sweatbands actually look ok & do work, I even get comments about them!

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I've had this problem. Do the need the bands to stick?

 

If not could you use a 'fluffy' hair band?

 

Nick

If you get the bands from a sports shop similar to those worn@ Wimbledon, they are elastic and & conveniently fit around the cylinder.

Every so often they can be removed, washed & replaced on the cylinder.ideal!

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I just keep the level 1/2 inch lower than it should and it seems to work. But I wonder about the safety of that.

Did anybody solved the problem of the crystallized oil exudate on the master cylinder?I have never understood where it comes from

Alberto

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If you get the bands from a sports shop similar to those worn@ Wimbledon, they are elastic and & conveniently fit around the cylinder.

Every so often they can be removed, washed & replaced on the cylinder.ideal!

 

Just found suitable bands on sale on Amazon in various lovely colours! Google sweatbands then link to Amazon.

79p each to soak that residue!

Cheers.

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  • 2 months later...

The plastic cover on my TR4's brake master cylinder is marked:

64474601 Use only Castrol Girling Fluid. Keep reservoir full..

This cover doesn't leak and is very easy to tighten/loosen.

I have a feeling that Land Rovers use the same master cylinder and have this plastic cover.

As it happens, I use silicone brake fluid.

Ian Cornish

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The plastic cover on my TR4's brake master cylinder is marked:

64474601 Use only Castrol Girling Fluid. Keep reservoir full..

This cover doesn't leak and is very easy to tighten/loosen.

I have a feeling that Land Rovers use the same master cylinder and have this plastic cover.

As it happens, I use silicone brake fluid.

Ian Cornish

Yes Ian I now have a plastic cap obtained from compbrake.com that appears to keep my fluid at bay!

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