Brakes Rear brake servicing

HarryMann: T25 rear drum brakes are common across all models and years.
They rarely get serviced, and whilst usually meeting minimum MOT requirements year after year,
they are often doing less and less of the braking. With more weight aft than many other vehicles, 
and a heavier vehicle overall, they make a big difference when working well.
Additionally T25 handbrakes have a poor reputation, again no doubt as they just squeeze through MOTs time and time again.

Brake shoe specs: Standard lining thickness: 6.0mm (0.236") Oversize lining thickness: 6.5mm (0.256") Wear limit: (0.098")

Brake drum specs: Diameter: 252mm (9.921") Max. dia. after machining 253mm (9.960") (use oversize linings after machining 0.5mm (0.020") or more) Wear limit: 253.5mm (9.980")

It is often best to buy new drums and standard shoes if the brakes are out of spec. A noticeable step in the drum friction surface at the inside edge can make removing them difficult, and prevent new shoes bedding in properly.

The VW part no for rear-brake shoe service kit i.e. springs and retainers (2-off, both wheels) is:-

251 698 545 (about £10 and well worth it even if just the retainers have rusted away)

Getting the drum off

Loosen the road wheel nuts slightly. Jack up the side or the whole rear and place axle stand(s) under the outer edge of the rear cross-member just inboard of the jacking point. Lower onto the axle stand and shove the vehicle around to make sure its secure. Remove the road wheel.

Remove the two retaining set-screws if present (the wheel will hold the drum on if these bind against non-standard wheels). When brake drum and shoes are well worn, this can be difficult.

The drum develops a lip at the back, where it overlaps the inner edge of the shoes. It also seizes/rusts onto the hub which is the lesser of the two problems... deal with this by striking it a healthy blow with a club hammer (not a small hammer that does damage.) You are trying to 'spring' the thin circular plate front plate that goes over the studs - which will flex safely - not distort the circularity, so strike square and flat onto the face, moving around. Start with medium blows and look closely at the join line around the hub behind the large 46mm nut for signs of release.

Alternatively, you can undo the 46mm nut (see Wiki elsewhere for tools) and take the drum off with the hub and splines. Alternatively a good small screwdriver can be edged into the retaining screw holes, but take care to do minimal damage, alternate between both holes. Deburr the inner edges before refitting!

To get a worn drum off over the shoes:

Ensure the handbrake is right off and cable has no tension on it. There are access holes at the rear of backplate (see link below) for the adjuster at the top. The aim is to loosen the adjustment off by spinning the self-adjuster, clicking it over bit by bit, but this is not an easy task! It'll usually either be seized, or the ratchet pawl will be locking it, but some persevere and loosen things off this way.

Re-fitting those shoes and springs

Photograph it all first? or memorise the springs. Haynes has a procedure, Bentley doesn't. Start at the top (strong) spring.

Make sure you put the top spring on the right way round and the correct side of the adjuster, they're all handed. Free up the adjuster well, set in neutral position to start. Long nose pliers, long thin but strong screwdriver, or a slotted one. It might help to have the bleed screw open on the cylinder (clamp the flexible hose) if you do it this way...

OR

...fit the spring with shoes loose, fit one fulcrum and lever other over the top cylinder with a healthy screwdriver, minding the rubber gaiters. Fit the handbrake cable and the bottom spring together then the shoe retaining cups (healthy pair of pliers just gripping edges, other hand behind backplate holding pin in place, line it all up and aim to do it in one go, elbow against body and lean into it, twist 90 degrees and release gently - they're the easiest of the lot)

The handbrake pull-up self-adjust rarely works (as the manuals suggests), even when al in good working order, so just keep popping the drum off (unless it's ridged badly) and clicking it up a bit on adjuster. Until it just rubs in one spot without binding after having centralised the shoes with the hand or footbrake (very hard). Otherwise, try adjusting self-adjuster clicker from access hole at rear, first check which way you need to flip it. It's best though to get the adjustment as close to final as possible first time, by slipping drum half way on, and guesstimating. Don't assume brakes are binding badly until after you've centred the shoes well, with handbrake or footbrake. De-dust drum everytime it comes off.

NB. Check not overheating after a good run out (spit-sizzle test).

If you lube the contact points/shoe fulcrums and supports, do this after its all assembled, Zinc based (Castrol PH) was always the right stuff (today MOS2 is often quoted), be sparing, long thin screwdriver to work it between the pivot points.

You might also inspect the brake pipe over the radius arm where it goes through the plastic clip for corrosion - I've had one burst there, as have others.

Rear brake backplate servicing

Hacksawbob some further thoughts

My brake pedal was pulsing and was diagnosed as a warped rear drum by syncronuts. the parts for a compleate rear brake service were about £60 from GSF this included a brake cylinder two pairs of shoes (L+R) and a drum. I was lucky in that my old drum came off quite freely it can take some persuasion with a lump hammer and a cold chisel and hitting left then right, top to bottom to free it up.

Tools you will need for shoe removal A safe method to jack and support your vehicle and 19mm socket to remove road wheels For drum and shoes only a pry bar for removing refitting return springs set of spanners lump hammer and cold chisel two pairs of pliers one needle one standard.

For cylinder removal brake clamp £4.00 halfords 11mm brake spanner £5.00 halfords 7mm spanner for bleed nipple ideally plus gas but at least wd40 13mm spanner for clynder bolt. brake bleed kit and compatible brake fluid 2.5mm-4mm cable ties for spring compressors

1. Put Plus gas the rear brake union now if you intend to remove the cylinder, also follow the brake pipe and put some on the unions on the forward edge of the trailing arms aswell, just incase the brake pies are corroded and disintegrate when you remove them. It may well be an idea to inspect those pipes they are a bugger for corroding. Your local garage may be able to make a spare up for you if it breaks.

2. put van in gear baut release the hand brake!

3. jack van, remove road wheel

4. remove drum (see above!) Mind the dust that is in it brake shoes have asbestos in them wich is bad for you. Also generally you should wear a dust mask if you are wire brushing any of the back plates etc.

5. Unhook adjuster spring and slaken off adjuster with a screw driver (looking from rear of the van near side slakens anti clock. off side is clockwise) and remove it note the long prong on the fork goes to the rear and on the far side of the shoe.

6. release return springs.

TOP TIP I found the best way was using a pry bar, the crank in the end gives you just enough of an angle to push the sping from between the hub and the shoe. saves your knuckles, about 2 hours and many curses.

TOP TIP it is possible to wedge them open agaist the hub and leave in situ if you only need to do the clynder and not the shoes. Hovever there is some finger loosing presure in them springs so go carefully!

7. Remove shoe retaining springs and cups, use the two pliers. Use the standard pair to hold the cup and the needle pair to turn the centre pin 90 degs. Remove cup spring and pin. Do both sides.

6. Pull top of shoes from away from cylinder then bottom. Shoes should come off altogether now after you un-hook the handbrake cable. Note how the upper and lower springs connect. Also note that the rear 'trailing shoe' has the handbrake cable arm and hook towards the outside of the van.

8. Now would be the time to remove and refit the brake cylinder if you are doing it. Apply the brake hose clamp to the rubber fexi pipe it the forward edge of the trailing arm. Undo the brake pipe with your 11mm brake spanner and. DO NOT be tempted to use a standard 11mm spanner it will end in rounded nuts, tears, and brake fluid. Go easy make sure you are going the right way and not tightening them (think about it, look at it from the rear just to make sure you are taking them anti clock.) Move it a touch, then nip it up again, undo a bit more, keep going back and forth undoing it a bit more each time. Cover the end of the brake pipe with a small peice of plastic bag to prevent dirt getting in to it.

9.Undo the 13mm bolt on the back of the cylinder.

7. Remove the brake cylinder, it may have rusted on to the back plate.

8. At this point you could refit the shoes the springs will be dead easy to locate as there is no cylinder to work against. Get them all nicely seated with all srings and handbrake cable atattched, Pull the top away from the centre pivoting around the lower seating point, then wedge them open with something about 4cm across like a sturdy block of wood. I used a wirebrush handle.

9. Refit new cylinder, clean the old bolt and do it up with a dab of copper grease.

10. Refit brake pipe union to cylinder and tighten (dont over do it!)

11.