RRC disappearing brake fluid , no external leaks

**PhilipA** · 4th May 2012, 08:12 AM

My 92 RRC without ABS has recently started to use brake fluid . I crawled underneath but could see no leaks. The amount is far more than could be explained by pad wear with about 50CC in the last 2 weeks. I filled it to the top mark and now it is at the seam of the reservoir .

So my assumption is that the master cylinder is leaking into the booster and being sucked into the engine.

But I recall when I last fitted a new master cylinder that they have a drain which directs fluid coming up the shaft back into the reservoir.

I will have a look tomorrow to make sure it is not a flexible hose or caliper ,( and maybe remove the master cylinder and have a look) but has anyone had the experience of fluid filling the booster?

Brakes feel entirely normal, no pulling, no loss of pedal, no sponginess, just the low level light.

Regards Philip A

**Dougal** · 4th May 2012, 08:31 AM

Are there any dribble marks on the booster from the centre down the face?

**tony66_au** · 4th May 2012, 08:35 AM

Hmmm, Booster is a probability yes and ive had this before.

The other possibility is heavy brake pad wear although unlikely in such a short time without noticeable drag, smoke or smell.

Id be pulling the wheels off and having a really good look, another possible cause may be a weeping brake hose squirting small quantities every time you brake and this can go unnoticed if it clears obstructions as degrading brake hoses can fail in a few different ways from ballooning to microscopic pin ****** and a good close inspection should reveal any damage.

Finally id check the bleeder nipples just in case.

Hope this helps!

Tony

**goingbush** · 4th May 2012, 08:52 AM

pull the vacuum hose of the booster, wipe inside the hose with one of your wifes cotton stick things, it should be dry inside.

**PhilipA** · 4th May 2012, 04:40 PM

It's the master cylinder.
I inspected all the calipers and hoses and all dry as a bone.
I undid the mounting bolts on the master cylinder and moved it forward and a trickle of fluid ran down the front of the booster.
Damn, although better that than a caliper because then you really have to do em all.
Regards Philip A

**Dougal** · 4th May 2012, 04:48 PM

Yeah same here. I haven't seen the trickle, but the evidence is there.

For me a new MC is 60 quid in the UK. I have replaced the seals twice, they last about four years a pop. Time to feed the cat a goldfish I think.

Thread: RRC disappearing brake fluid , no external leaks

Thread Tools

RRC disappearing brake fluid , no external leaks

Bookmarks

Bookmarks

Posting Permissions