VW Polo 1997 - Handbrake Adjustment Difficulties

[bauerjan]

Good afternoon everybody.

I set out originally to replace the rear wheel bearings on my 1997 VW Polo. A video on YouTube showed a young fellow completing the job in 2 Mins.

However, I ended up replacing the bearings, one wheel cylinder and two brake shoes ( horrendous). @ Burnerman's advice was most helpful

Having completed the job I was well pleased until I discovered that I was now having problems with the hand brake adjustment.

My problem now is that when I attempt to adjust the cables, inside the car, there is an inbalance. I am practically running out of thread on one cable, while the other one still has adequate thread to spare.

My gut feeling is that perhaps one cable has stretched and may need to be replaced.

The handbrake was always a bit "iffy" despite having been adjusted by a professional mechanic on a number of occassions.

Any advice would be most welcome!

Regards,

Jimmy

 

[Burnerman]

Hello Jimmy
I think there's a strong possibility here that one of the wedges hasn't dropped into place to adjust the shoes on one side....quite common actually!
Pull the handbrake on a few clicks, and check to see if there is equal drag on each rear wheel.
If you suspect my wedge theory, its possible to see the base of the thing through one of the stud holes....with the handbrake on, a fine screwdriver can be inserted into the spring hole to yank the wedge down into place.
Another trick is to have the handbrake and the footbrake on, whilst giving the drum a sharp tap with a hammer - often has the same effect.
John

 

[bauerjan]

@ Burnerman

Hello John - many thanks.

Initially with the handbrake on, one drum was locked while the other one was easy to spin.

Am I correct in thinking that the wedge plate, that may not have dropped, is in the drum that is easy to spin?

Regards,

Jimmy

 

[Burnerman]

Yep, absolutely right Jimmy.
The trouble with these things - if the serrations on the wedges are particularly sharp, they grip on the shoe and don't let go. If the serrations are worn off, the wedge happily slides back up again
If you still have trouble, pop the drum off ( I know, its a pain with the taper roller bearings) tug the handbrake cable as it enters the backplate and see if the wedge descends a bit. You can always push it back up if the drum doesn't want to go back on.
John

 

[bauerjan]

Hello again John.


Are you suggesting that even though I yank the wedge down there is a possibility that it may move up again?

Is it not held down by a light spring?

Is it possible that I might have to renew the whole spring mechanism?

I am not too clear how the wedge actually functions. Under normal operating conditions, does it move?

Thanks again for your patience.

Regards,

Jimmy

 

[Burnerman]

When you depress the footbrake, the pistons move out of the wheel cylinder and force the shoes into contact with the drum.
Every once in a while, as the shoes wear, the wedge moves down its groove (assisted by the spring) and the serrations on the wedge make it stay there. Its only if the serrations on the wedge have gone that it tends to slide back up again.
This takes up the shoe wear - without this, the brake pedal travel would be too long.
If you have an assistant handy, pop the drum off one side, press the footbrake slowly and you'll see what I mean.....the wedge should pull down a fraction, and stay there. By prising the shoes apart its possible to push the wedge back up.
John

 

[bauerjan]

Good Morning John,

I see that, like myself, you appear to be an early-bird!

Many thanks for your explanation.

It would appear to me that the wedge plate has taken the place of the 'adjusters' of old. However, instead of having to re-adjust the adjusters as in the older system, the wedge plate does the adjustment automatically.

I will carry out the checks that you have outlined.

Best Regards,

Jimmy

 

[bauerjan]

@ Burnerman

Hello again John.

As an update to my previous post, I removed the drum and I found the handbrake cable was lying across the lower return spring. I suspect that it should run in a channel - behind.

The wedge plate is fully down - yet I had no trouble removing the drum. Is this strange? The top of the wedge plate is level with the top of the piston of the brake cylinder. The wedge plate is inside the shoe nearer to the backplate. Is that OK.I am giving this information in case I reassembled the brake assembly incorrectly.

Your comments would be much appreciated.

Regards,

Jimmy

 

[Burnerman]

Do sort that cable Jimmy - I think there is a channel for it behind the shoe.
Regarding the brake drum, the adjusters aren't supposed to keep the shoes actually in contact with the drum, rather than keep them very close.
You may have seen a wear lip on the inside of the drum, where the shoes don't actually rub. If this is ground away then the drum removal is simple for the future.
I don't think you have the shoes assembled incorrectly - usually they won't fit back onto the backplate for any price.
From memory - the wedge should slide between the shoe and the fork that connects to the other shoe, and the part of the shoe that the wedge grips to should have serrations also.
Be lucky!
John

 

[bauerjan]

@ Burnerman


Hello John,

I have correctly relocated the brake cable.

The wedge is fully down.

There is still a huge inbalance between the two brake cables.

The suspect one is at the limit of its adjustment. The handbrake is barely useable with the lever pulled up above 7 notches.

To me it seems that the cable has become stretched. I think that considering the year of manufacture (1997), this a possibility.

Replacement of the cable seems straightforward according to the Haynes manual. Are there any hidden, unforeseen, difficulties?

Best regards,

Jimmy

 

[Burnerman]

Hi Jimmy
It seems like there's no option left now but to replace the cables.
No real problems here other than access....I wouldn't mind betting that one cable is actually ready to part completely - usually this happens where the outer plastic sheath cracks and allows water in.
I have to recommend replacing both cables really - its a bit of a faff but could pay off at the end. The handbrake movement will be superbly smooth and positive after!
Burners tip of the week to check handbrake function......coast down a hill at about 20 mph, and gently tug the handbrake - the car will tend to squat down at the back (don't lock the wheels)! You'll be able to feel which corner squats more, and this is the side that is working.
John

 

[bauerjan]

@ Burnerman

Thanks John,

Regards, Jimmy