burning brakes ?

[paulweld]

Hi all newbie to the club ! but not new to vws ! and in the process of buying my first T25 ! well to the point now i ve just done a fair overhaul to my mates brakes front and rear for the mot went through no probs but he took it for a drive to return with very hot front wheels/brakes !! now thing is i cleaned/filed/wire brushed and moved pistons in/out cleaned them as well/ new pads checked they fitted ok etc also bleed braking system three times to run new fluid through and remove air !! ( new wheel clys on rear etc ) wheels spun freely and tested for braking and releasing no probs now is it possible for the master cly to play up and not release braking pressure ? ( i think there is a non -return valve in there that can fail ) any help please !! not had a chance to look at it yet !!

[VWCamperfan]

I'm going to guess there's actually nothing wrong.
These brakes do get quite hot even on just a short run and only braking a few times.
If it passed the mot the I would imagine they are ok but just to be sure jack up each front wheel and try turning by hand after applying the brakes with engine running and see if they are releasing.
There is a small air filter on the brake servo unit that can clog and partly stop the brakes from coming right off but it's unlikely.

[Red Westie]

The point is.....are they binding in anyway? check when hot! is the van rolling at slow speed? the most accurate check would be to jack up and spin each wheel to see if it turns easily (after a run so they are hot) but as VWcampervanfan says..they do get hot so as long as they are not binding.
As for a filter in the servo unit? I take it you mean vacuum line? anyway if this were blocked the fault symptom would be the brake pedal going hard and the brakes needing to be pressed very hard to stop the van (it wouldn't stop the brakes coming off) that sympton usually indicates sticking caliper pistons or seized pads which seems unlikely in this case given the recent maintenance.
As for master cylinders sticking..again never heard of it happening.
Remember the new pads will require bedding in to the old discs, they can overheat if they are worked to hard (until they have properly worn to the shape of the old discs 200-500miles) the new pads will only be touching in spots until bedded in so take it easy.
Martin

[HarryMann]

cleaned/filed/wire brushed and moved pistons in/out cleaned them as well/ new

.. and the state and thickness of the discs was?

[paulweld]

The thickness of the discs is ok some slight scoring but not bad by any means ! new pads fitted but the point was they were hot and smelling which was a surprise after the amount of cleaning etc i give the calibars did jack up the van while still hot and would turn with small amount of binding not enough to cause heating probs like happend ! you would think they were not releasing but it does not seem that way But?

[phade]

Is the brake burning coming from the front or rear brakes ?

If they're coming from the rear brakes then are they partially sticking when you try to release the handbrake and pull away ?

If either or both are the case then a brake spring could be weak or broken.

My campervan's rear N/S stuck on about a year and a 1/2 ago and the only way I could release it was to drive forwards. It turned out to be a weak brake spring and replacing all of the brake springs on the rear N/S brakes cured it.

[HarryMann]

The thickness of the discs was OK

10, 12, 14 or 16mm ? 12mm is minimum spec, the rear drums also have a max wear limit and circularity limit.

If there's slight binding then maybe it IS the fronts, it doesn't want much maybe the pads want bedding in over a longer period gently raising the heat and braking force over an extended period. You should be able to determine where the smell is coming from...

Yes, handbrakes can stick (esp. in freezing weather)... complete repair spring packs can be had for about £12 (or could). New rears can be a bit of a sod to get adjusted right IMHO, esp if the drums are ovalled, drive-flange distorted or new shoes. I have been known to file them (shoes) up a bit

[paulweld]

Hi harrymann it is the front brakes for sure as they were smelling and hot ! the rear are fine as i did a full overhaul on them new brake shoes/cyl/h/brake cables/spring set/brake hoses and all new copper brake lines on rear ! also adjusted the rear brakes with that tool you can buy and they are fine etc i think i will take it for a test run and see what happens could be they want bedding in ! failing that i will strip and check it all again and maybe sand the pads a small amount to increase clearance as they may a bit tight but it did not seem that way !keep trucking as they say lol

[phade]

That sounds like a siezed brake caliper (or both).

This happened to my polo four years ago when the front N/S was smoking !!