Hi

I recently renewed my 1997 1.0 polo's rear shoes, drums and cylinders. I've done about 350 miles on them. The brakes feel fine.

I just failed my MOT RBT service brake efficiency 40%. The mechanic told me he would need to just adjust the rear brakes. However I told him that they are self adjusting, he said there is a screw that needs to be turned. I know this is not true, as I renewed the brakes myself. So I'm trying to work out why they are not efficient to pass the MOT.

I could be about to answer my own question.... I renewed all the springs apart from the self adjusting spring, as the replacements in the pack were different to the ones I had. I understand from the haynes manual that they may be attached in different configurations.

Does anyone have a picture or description of how the alternative springs fit? Mine (pictured) currently go down through the push rod to the third hole (attached below the push rod). From what I can make out the other configuration goes to the second hole (above the push rod)

In your opinion could this solve my problem, or could there be another reason for 40% efficiency. As I'd like to explore all avenues before my retest.

Thanks

Edited 28 September, 201015 yr by Electrobumps

your self adjusting wedge is quite low, thats why the vertical spring on the right of my picture is more stretched, try pushing the wedge pin up, the haynes describes something about it, not too sure about the specifics

From what I can remember I pushed these up, the pic is pre overhaul. Do these not get released when you hit the brakes, Not sure on that though? I notice you have the same spring config as me. Did you buy new spring sets? Where did you get them from?

Cheers

Edited 28 September, 201015 yr by Electrobumps

new springs come in a fitting kit ..should get one from any motor factor

what you want to do once its all fitted is leave a wheel bolt out and use a pointy screwdriver or someting to poke in that ajuster wedge ..mess with it until the shoes are almost touching , you dont want it binding but you can prob get em so they're nice n close

i find i have to do this once in a while to make mine 100%

When mine failed, on a similar problem, i just went around and greased everything (not the shoes obvs). Maybe something simple like tis may help?

When mine failed, on a similar problem, i just went around and greased everything (not the shoes obvs). Maybe something simple like tis may help?

well my initial thought when looking at that picture with the new shoes is that everything looks a bit dry. I usually grease all the moving parts up, except the friction surfaces obviously! They are self-adjusting in theory but the mechanism rarely works well without some encouragement.

When mine failed, on a similar problem, i just went around and greased everything (not the shoes obvs). Maybe something simple like tis may help?

well my initial thought when looking at that picture with the new shoes is that everything looks a bit dry. I usually grease all the moving parts up, except the friction surfaces obviously! They are self-adjusting in theory but the mechanism rarely works well without some encouragement.

My picture shows the discs and pads before they were renewed. So I greased the top buy the cylinders and at the bottom of the shoes, should I do else where? How is the best way to test or know that you have made the shoes close enough to the drum?

With regards to the new springs, the new self adjusting spring was different. As it say in the haynes manual there are different configurations for the self adjusting spring. So I do not know where I should put the new self adjusting spring. So I went with the old spring in the original config.

From what I can remember I pushed these up, the pic is pre overhaul. Do these not get released when you hit the brakes, Not sure on that though? I notice you have the same spring config as me. Did you buy new spring sets? Where did you get them from?

Cheers

all items in the picture were from GSF, but I had a set of pre-built 200mm drums from VW which I used as a template when fitting the above in the piccie.

twas my first time doing drum brakes, and wasnt too bad!

the above setup pictured passed the MOT fine with regards to braking.

good luck in sorting yours out mate!

You need just the merest dab of COPPER-GREASE apply this to all of the metal-to-metal contact surfaces. (don't use hub bearing grease, as this can spread and contaminate the friction surfaces.)

If the auto-adjusters have failed to work, you will have a lot of brake pedal travel, also the hand-brake may come back further than normal.

If, by any chance, you have adjusted up the hand brake cable to try and compensate this, then slacken off the cable again and try pressing the pedal a few times to ratchet up the auto adjusters, if this fails, you may be able to work through the wheel bolt holes as has already been suggested.

If none of this makes any difference, remove the drums again and have a look at the new linings, they should, by now, be showing any high-spots where they contact the drums, rub these down with some wet-or-dry paper (or similar) to obtain an even surface on the lining.

Never try to 'bed in' new linings by heavy use off the brakes or driving with the brakes applied, all that that will achieve is putting a glaze on the linings and taking even longer to bed in.

Regards.