Club 80-90 Forums

Posted: **21 Oct 2008, 14:19**

I had same, common problem, it was master cylinder. £70 supplied and fitted

Posted: **21 Oct 2008, 15:26**

Hi, thats a great price, where about is that mechanic based please?

Dave

Posted: **21 Oct 2008, 19:38**

Red Westie wrote:The Servo has nothing to do with it! the master cylinder is simply leaking into the servo, don't be conned into believing you need both! or that you need to have both fitted as a matter of cause.
And to e3....
Servo seals What the blithering heck? you are getting duff information, sounds like the guy doesn't know what the hell he is talking about! if the servo diaphram fails the pedal goes hard and you get no braking assistance! this results in very poor and dangerous brakes....but very easily diagnosed ie:
After the engine has been turned off, pump brake pedal until it goes hard (normally 3-5 pumps) whilst applying moderate pressure to the brake pedal start the engine......the pedal should sink and go soft which indicates CORRECT servo operation, if it remains hard the servo is foooooooked or there is a problem with the vacuum supply or one way valve in the servo.
If the servo leaks....it leaks air not brake fluid (unless of course the master cylinder is leaking fluid into it)
I was also going to mention that on petrol engined vehicles which take their vacuum off the inlet manifold (Diesels have a seperate pump) on a vehicle with a leaking master cylinder the brake fluid is often sucked into the engine through the vacuum pipe which can result in excessive engine smoke (in extreme cases)
Martin

maybe i misheard the mechanic., but if the fluid is sucked into the engine is that maybe why my exhaust is very smoky? but its only very smoky when it starts, then it fades after 5 minutes? (or is that for only petrol engines

[IMG:703:527]http://i415.photobucket.com/albums/pp235/72r/smk1.gif[/img]

Posted: **25 Oct 2008, 18:27**

wow, that is smokey.... could be a head gasket, yours is watercooled right?

i just ordered the brake master cylinder, gonna fit it myself... credit crunch and all that

David

Posted: **25 Oct 2008, 21:26**

e3....yes for petrol engines that take the vacuum supply from the inlet manifold. Diesels have a vacuum pump so when a servo fails the fluid doesn't end up in the inlet manifold.
Smokey when starting (Diesel?) could be glow plugs, could be valve stem oil seals, could be turbo seals........
Martin

Posted: **26 Oct 2008, 13:41**

davidvincent wrote:wow, that is smokey.... could be a head gasket, yours is watercooled right?

i just ordered the brake master cylinder, gonna fit it myself... credit crunch and all that

David

yes watercoold. havnt been to the garage to get the brakes fixed yet. will tell you when

Posted: **03 Nov 2008, 16:02**

Ok, so I have the old brake master cylinder off and am installing the new one... one thing i noticed is that the new one has an extra hole on the underside, i think it could be for an extra 'warning switch' or similar, my question is... do I need to block it with a bolt to stop fluid escaping? The part was not supplied with one and I don't have any the right size!!

thanks in advance!

Dave

Posted: **03 Nov 2008, 18:12**

I am not certain but I thought all T25s have 2 switches on the Master cylinder that 1/do the brake lights and 2/ the brake failure warning light on the instrument panel? Do later models have a third? and if so what is it for?
There is also a bolt on the underside that is the secondary piston stop.

I would think that if the new master cylinder is not a direct replacement you would be better getting the correct one.

Incidentally I have never seen it written anywhere but after you bleed the brakes the brake failure warning light might stay on. To get it to go off (provided you know everything is okay) either disconnect the battery or remove the connector on the back of the brake warning light. (My van is 1984 vintage)

Trundletruc

Posted: **03 Nov 2008, 18:32**

Hi

Basically I think this T25 has the same (more basic) brake master cylinder as a T2 Bay as mine was built in 79 and registered in 80, then again i'm on a learning curve myself here. I could be wrong but I dont even think my instrument panel has a 'brake warning' light at all...

On my original cylinder there was only one hole tapped for the one switch, the new one has an additional hole, not including the piston stop bolt you mentioned.

It doesn't help that the suppliers basically crossed their arms and apologised but said they neither supply the additional switch or a bolt/plug to fill the gap. The listing does state "...suits all T25's from 79-90 that have a servo unit" which mine does, I think unless anyone has any better ideas I will just find a bolt to plug it.

Onwards!

Posted: **03 Nov 2008, 20:22**

red westie , i still can`t get me head round a dg engine , like mine , burning brake fluid .

HOW does it get into the inlet manifold/ vacuum system ? ?
jaylo

Posted: **06 Nov 2008, 22:32**

your servo works off engine vaccume so if theres fluid leaking into the servo it will get sucked into the motor (which is creating the vaccume)

Posted: **06 Nov 2008, 22:34**

Picked up our T25 last week. Having a proper nose about once I got it home, and have also found a fluid leak in the drivers footwell,
A previous owner had wrapped an old sock around the top of the brake pedal to soak up the fluid!!
What I can't establish is if the leak is clutch or brake cylinder related, both look a nightmare to access due to their location behind the dash.
Also the brakes seem to work ok. In my experience once you get a fluid leak your pedal hits the floor and you ain't stopping....

Posted: **06 Nov 2008, 23:11**

i had the same issue, couldnt tell if it was the brake or clutch master cylinder. i took out the instrument panel (so you can clearly see the brake cylinder) and then pumped the brake pedal, i then saw a small amount of fluid leaking from the brake cylinder, indicating that was the part that was failing. also dot 3 brake fluid will eat into paintwork so if your servo unit is looking like the paint is bubbling/deteriorating then you know what is the problem.

it's easy to take out the instrument panel and removing the brake cylinder only requires basic tools. i am finishing off the job on saturday (including bleeding the brakes) so i'll let you know how it goes!

bit nasty what the last owner did to you, i'd be tempted to post his sock back to him!!

dave

Posted: **07 Nov 2008, 18:58**

Had another quick look today, and your right the instrument pod came off easy, and by twisting my neck into an un-natural position and looking down I could see the master cylinder and servo unit, packed amongst looms of cable.
I pumped the pedal a few times, and could not see any leaks, the fluid however began dripping from above the pedal. I'm suspecting the clutch slave, but further investigation will be required.

Posted: **08 Nov 2008, 11:44**

i had this with my elderly velle some years ago, i took the dash clocks out, and sprinkles flour down onto the top of the servo and master cylinder and clutch cylinder, then put the clocks back and used it for a week (Maybe a month, cant remember) then later took it out again and could see where the flour had tracks of fluid running and diagnosed the brake master.......

as for the late early amount of holes thing, just buy another brake light switch and screw in, only a couple of quid, and you are carrying a spare when yours fails , to swap over.........

Club 80-90 Forums

Brake Fluid leak in drivers footwell

Master cylinder

Fluid leak in drivers footwell