Thread: Brake Problem

bet youve got generic replacement shoes and they are not radius ground, set up as lead/trail or chamfered correctly.

I can see tthree possibilities. The obvious one is, as you imply, that the drums are not machined to the same diameter over the width of the contact surface, perhaps by not being machined right at the inside edge. This seems unlikely to me, particularly if the machining was done by a competent brake outfit.

Rather more likely is that the brake shoes are not sitting straight. There would be two likely causes for this. The less likely one is that they are the wrong shoes for the job. More likely is that the brake shoe return springs are incorrectly installed - they go behind the shoes so that they pull the shoes back against the stops on the backing plates. These stops are pressings in the backing plates and are not adjustable, except on early Series Landrovers (Series 1 and 2 and perhaps early 2a from memory, without looking it up, but remember the bits on yours may have come off a different model!) where there is an adjustyable post, which needs to be set. Whether this is the problem can be checked by measuring the distance between the edge of the shoe and the backing plate at several points - should be the same everywhere.

The third possibility is that the drums are being pulled crooked as you tighten the screws. This would be caused by either foreign matter on the drum or the mating surface on the hub, or burrs on either part, in the case of the drum, possibly from the machining operation or damage to the edge of the screw holes.

Hope this helps,

John

Reubs

Most likely is as John suggests the shoes are not fitted correctly. Otherwise did you fully close the cylinders before fitting the drums?

When you say get the drums machined, did you do that at all? If not and you have scored drums, they may ramp up to the edges causing your binding problem. In which case you do need your drums machined.

Remember, when you have machined a drum oversize, you need oversize shoes to match.

Diana

Hi all thanks for your helpful replies. I do like Dave's reply best. I'll try to get some photos shortly but for several reasons it seems very likely that it is the shoes at fault:

I installed new wheel cylinders as mentioned.

The were pressed all the way in when installing the drum.

Opening the bleed nipple on the cylinder won't aleviate the problem.

There is not contact all the way around, i.e the shoes are contacting the drum at the top only (maybe the bottom as well).

The drum seems in good condition (no scoring that I can see).

I'm fairly confident the shoes are installed correctly (springs are going behind shoes (and top spring behind the snail)

The snail is adjusted properly (a photo will confirm this).

Also the stops on the backing plate (not adjustable) are in contact with the shoes.

I'll give the supplier a call and see what they think the shoes were sold on an exchange basis so I can't put the old ones back on for any experimenting.

Here's some pics...

And more...

I also assume the the shoes were aligned vertically.

If you can see scores on the friction surface of the shoes where the drum was pushed in, then you may be able to "fit" the shoes yourself. Using a wood rasp, the type with the teeth like a continuous curve, or coarse sand paper on a hard block. Re-shape the shoe along the direction or rotation, so that you taper the end where the score marks were evident. Continue in short shaves checking frequently by offering the drum up to the hub. Stop when you can first fit the drums and do up the screws without jamming the wheels.

The shoes will round themselves the rest of the way in service.

Thanks very much Diana.

Is this a common problem or is it caused from cheap shoes as Dave's post would imply?

Thanks again John and Dave as well, maybe the Rover will finally leave the uni carpark, she's been stranded the last 10 days.