VW Polo - Rear Wheel Brake Shoes Replacement

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I recently replaced the bearings in the rear wheels on my VW 1997 Polo.

When replacing the drum I noticed that one of the brake linings was cracked right across, along a line where the lining was riveted to the shoe.

I am trying to replace the shoes but I am finding it very difficult to disconnect the hand brake cable. Has any one any ideas on how to disconnect the cable? Is it usually tricky to disconnect?

I also noticed a problem with one of the wheel cylinders. The surface on which one of the shoes rests is almost completely flat. Could this allow the shoe to slip off and lose contact with the piston of the wheel cylinder?

What does replacement of the wheel cylinder entail? Would it be necessary to bleed the whole brake system following replacement of the wheel cylinder?

I have a Haynes manual on the car.

Any information would be most welcome!


Regards,

Jimmy
 
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Good evening Jimmy
Welcome to the world of the rear drum brake! To release the cable is an art...or more likely a pain in the arris......
Do one side at a time, so you can refer to the other if things go adrift.
Release the shoe hold down springs and clips, then lose the bottom spring that holds the shoes together. This allows you to pull the shoes clear from the back plate, and turn them towards you so you can see the cable end.
I pull and hold the spring on the cable back with some pliers (actually cutters) so the nipple can be wriggled out of its socket.....easy enough to suggest from the comfort of a laptop but less so in reality! Using the cable, pull the lever from the shoe which allows you to disconnect.
Regarding the wheel cylinder, I seem to think that there is a lip on the cylinder piston to sort of locate things, but don't worry about this as the shoe hold down clips will keep everything in order.
If you want to replace the wheel cylinder, its held on by 2 10mm bolts, if memory serves. The difficult bit is releasing the solid pipe from the back.
The bleed nipple will snap off anyway as its made from plasticene but that doesn't matter - the new cylinder will come with a new one.
You will have to bleed after but its dead simple. With a helper, less than a minute.
Good luck with this - once you've done one side you'll be an expert - until the next time!
John :)
 
@ Burnerman

Many thanks John for your prompt reply.

I fiddled around with tha handbrake cable for quite some time without success. Must the cable adjuster inside the car be really loose?

Secondly, will it also be difficult to re-connect the cable when replacing the shoes?

Your assistance is much appreciated

Regards,

Jimmy
 
I guess the looser the cable is, the easier it is to connect and remove but personally I don't bother....I pull the cable (when its still connected) with my pliers which brings the operating mechanism clear from the shoe itself - sometimes I hold the lever there with a small 'G' cramp to help me and then I twist the cable end free. Its certainly a knack though! After a while you'll get the hang of twisting the shoes around to get them back on the backplate. No way will you be able to connect the cable unless the shoes are both released from the backplate.
Usually I only disconnect the lower shoe spring and leave the upper ones alone, but thats just my technique.
A small tip when dealing with the new shoes - cover the linings with masking tape then it doesn't matter how much crap gets on them - its peeled off when the job is done.
John :)
 
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@ Burnerman

Good evening John

I am glad to tell you that I have succeeded in detaching the handbrake cables and removed the shoes - thanks to yourself.

However I have run into another problem while fitting the new shoes.

The Haynes manual tells me to:

Apply a little brake grease to the contact areas of the pushrod and handbrake lever.

Hook the tensioning spring into the trailing shoe. Engage the pushrod with the opposite end of the spring, and pivot the pushrod into position on the trailing shoe.

Fit the wedge key between the trailing shoe and pushrod, making sure that it is fitted the correct way around.

Everything is ok until I come to fitting the wedge key.
The manual indicates that it is simply a matter of pushing the wedge key into position. However, I find that the gap is too small.

Any help would be most welcome

Regards,

Jimmy
 
Jimmy, its Popeye hands time.....spread the shoes just enough to allow the steel wedge to go where it needs to - this is where your third hand comes in :p
Usually I fit the shoes together on the bench, minus the bottom spring but complete with wedge in place. I then offer these up to the backplate, connecting the handbrake cable as I go.
John :)
 
@ Burnerman

Hello once again John.

At this stage I am sure that you are thinking that "this fellow in a PITA."

However, some years ago I totally renovated an old Beetle, taking the engine down to it's last nut and bolt and replacing the whole braking system etc. So, I have some experience.

However, this rear brake shoe replacement is giving me some grief.

I will insert here once again the instructions from the Haynes manual:

1. Hook the tensioning spring into the trailing shoe. Engage the pushrod with the opposite end of the spring, and pivot the pushrod into position on the trailing shoe.

2. Fit the wedge key between the trailing shoe and pushrod, making sure that it is fitted the correct way around.

My Problem
==========

If I carry out instruction 1, I cannot insert the wedge key. The gap is too small - I was tempted to try to hammer it in - seems a bit drastic!

If I detach the spring from the pushrod, I can fit the wedge.

Now, of course, the problem is, how do I stretch the spring to re-engage it with the pushrod. Is there a tool that one can purchase to stretch the spring?

I am dealing with one shoe - the shoe that the wedge operates on.

I was considering screwing the shoe to a piece of wood which I would clamp to a bench and then try to stretch the spring.

I am sure that the problem is quite elementary to you and I would be most grateful if you could guide me once again.

I have tried to stretch the spring with a pliers without
much success!

Best regards,

Jimmy
 
Good evening Jimmy - I'm so sorry that you are having such a struggle with this, but in no way would I ever consider anyone to be a PITA for having a go....completely the opposite in fact :p
So - everything works fine with the shoes, minus return springs - on the bench. The problem is engaging the springs then fitting the shoes to the backplate, and overcoming the spring resistance.
Point number one - you'll never pull brake springs back with pliers, they are too strong and the pliers always let go.
So, there has to be another way.
Try securing the forward shoe (doesn't matter which side) onto the backplate with its retainers. The other shoe - brake cable connected - try to hook this up onto the wheel cylinder (without splitting the rubber seals if you can).....you'll get much more leverage by pivotting the shoe than you would trying to pull the spring. Often you can place the shoe edge on the wheel cylinder piston, and heaving it into place.
Leave the bottom spring disconnected for now, that can be fitted later if you succeed in connecting the shoes onto the wheel cylinder.
The only other thing I can suggest is that using an adjustable spanner on the ends of the shoe may help you to lever the things into place.
Be lucky!
John :)
 
@ Burnerman,

Hello John,

I have more or less solved the problems encountered in replacing the brake pads - many thanks.

As I mentioned earlier, I was a bit unhappy about the condition of one of the wheel cylinders and I have decided to replace it.

I have looked around for a replacement cylinder and have been given two options:

a. Quinton Hazel BWC 3580 - diameter 17.5 mm.
b. Quinton Hazel BWC 3733 - diameter 19 mm.

Could you suggest which component would be correct for my 1997 VW Polo!

Best regards,

Jimmy
 
Afternoon Jimmy
Sadly it could be either of these cylinders, but the easy way is to peel back the rubber boot so the piston is exposed and measure the thing with a caliper or similar.
I believe they are handed, too.
Take great care to slacken the brake pipe as most spanners will round it off, and this is where Mole grips come in. The cylinders fix to the backplate with allen screws I think but it could be 8 or 10mm short bolts. Shift the pipe first, and when its free plug the end with one of the rubber caps that fits over the bleed nipple, if they are still there.
Cheers
John :)
 
@ Burnerman

Good evening John.

Thanks again.


Just to be 100% sure, can you confirm that I should measure the diameter of the piston. This measurement should then be either 17.5 mm or 19 mm.

Just being ultra careful!

Regards,

Jimmy
 
Yes, thats absolutely right, measure the piston diameter.
With only 1mm difference - don't ask me why but I think its because some models had a weight compensator fixed to the back axle.
I also don't know what difference 1mm would make to the brake performance, but there's always a chance that one wheel cylinder could be slightly longer than the other, hence replace like for like.
Have a good evening!
John :)
 
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