UKCRC Forum

Technical => Wheels, Tyres, Brakes, Suspension => Topic started by: chris27_blue on Jan 12, 2025, 04:35 PM

Title: Brake fluid reservoir leak
Post by: chris27_blue on Jan 12, 2025, 04:35 PM
Have a joint brake/clutch fluid reservoir on my DAX

A few month back was leaking a bit from the reservoir cap. (Even caused the clutch to fail at one stage)

Anyway, after inspecting the reservoir cap and seeing a rusty flange type piece, and the rubber failing, (after trying to repair) swapped it for an identical one from Car builder website

It seemed a perfect match, but it still leaks a little bit

Is there a brake fluid resistant sealant, or tape, that i could put on the thread to stop the weeping, rather than have to swap the whole reservoir out?

Apparently you cant use PTFE tape.
Title: Re: Brake fluid reservoir leak
Post by: JON1D on Jan 12, 2025, 11:32 PM
It is not clear where is the leak now. Always try and find out why you have the leak. if its on the low pressure side pipes then the pipes or clips might need replacement. Never mess with brakes always replace of fix. I would stay away from any paste or tape as a repair it will only fail in the future when you least expect it to.
Title: Re: Brake fluid reservoir leak
Post by: chris27_blue on Jan 13, 2025, 04:50 PM
Quote from: JON1D on Jan 12, 2025, 11:32 PMIt is not clear where is the leak now. Always try and find out why you have the leak. if its on the low pressure side pipes then the pipes or clips might need replacement. Never mess with brakes always replace of fix. I would stay away from any paste or tape as a repair it will only fail in the future when you least expect it to.

The leak is coming from the reservoir cap

Only solution is to replace the reservoir itself i suspect
Title: Re: Brake fluid reservoir leak
Post by: chris27_blue on Mar 31, 2026, 09:28 PM
As an update to this thread, fluid was being drained from the brake reservoir by being drawn through the vacuum pipe and being burnt in the cylinders.

This only happened occasionally when brakes were used hard over a period of time. I didnt put 2 and 2 together, that problem resolution was thanks to Pilgrim Motrosports who took a while but ultimately diagnosed the unusual issue.

A new servo  and master cylinder solved that problem.