11 replies to this topic

[Tornado99]

Is there a wear limit for rear drums? Haynes only lists a shoe friction layer limit (3mm).
Ive been trying to solve an issue with my handbrake, forward single cable is at the max tension on the adjustment thread. With the rear shoe adjusters set to give a stiff wheel turn, the handbrake will not hold car on slopes during pull aways, no matter how hard I pull it up (typically max I can do is four or five clicks).
New shoes, new cylinders, new adjuster bolts/slides, new springs and new cable levers. The cables themselves look near new, no visible rust etc. Can't believe stretch is culprit as the adjuster thread is 1-2" and it all used up.

I have a new set of cables to try but could the issue be the drums are worn?

[Spider]

Yes there is a wear limit. I have it as 3/32". Usually when the drum gets over-sized, it needed machining to true up. The first over size is 1/16" over at which point over-size shoes are needed, though, I'm not sure if anyone supplies them these days.

[sonscar]

Check for wear in the pin the actuators in the drum pivot on,they can kind of "cockle over" if worn which badly compromises the handbrake.Steve..

[GraemeC]

Did you back the lever adjuster right off before adjusting the shoes?

[Tornado99]

Check for wear in the pin the actuators in the drum pivot on,they can kind of "cockle over" if worn which badly compromises the handbrake.Steve..

Yes I took this advice from someone when I first reported the issue a few months ago. Lastnight I swapped out the old levers with new...could not see any visible wear and the pivot point seemed to have about the same "wiggle" amount as the new levers. We'll see how she goes after a bit of mileage. 

[Tornado99]

Did you back the lever adjuster right off before adjusting the shoes?

Yes I unwound the cable adjust quite a few turns...cable felt some slack and the shoes were not holding the drums tight with the rear adjustment bolts turned out. I set the adjuster bolts so the wheel was somewhat stiff to run by hand before winding the cable adjust back....ended up at same max tension point, no further thread on the cable stud. Wheels still at same stiffness to turning. One handbrake click gets them pretty hard to run by hand...two not possible to turn. Just did this lastnight...but did similar some months ago and it wasn't long before 4-5 clicks were needed to hold car on a slight incline...progressed to no holding possible on medium to steep slopes at max I can pull the lever to. 

[weef]

New drum internal diameter is 177.8mm.  Maximum internal diameter is 179mm.

There is only a 1.2mm wear limit in the drum diameter, does not sound very much but it takes a lot of braking to wear them out. Brake drum do not tend to wear flat or even, run your finger over the surface and you might notice they are worm and feel slightly convex. As the wear limit is so small it is not worth skimming them. 

If the drums need replacing then you also require a shoe set and a fitting kit, pull off springs and pins.

If you think the parts fitted at present are servicable then proceed as follows.

Completely back off the adjuster at the handbrake lever end and check the cables, radius arm swivels and the levers at the drum end are all free moving..

Inside the drum check the friction material is good and oil free, the bonding to the shoe is secure, the pull off springs and pins are good and fitted correctly and the orientation of the shoes are correct, remove the adjuster screw completely and inspect it and the adjuster sliders for wear and replace any suspect parts.

Ensure the hydraulics are good, peel back the piston dust covers and check there are no fluid leeks evident and ensure both pistons are free to move.

Once you are sure all parts are servicable and fitted correctly refit the brake drum and adjust up until the wheel just locks, tapping the drum with a mallet as you go to help centralise the shoes and press the brake pedal once or twice during this operation as well. Remember when adjusting the brakes always set the adjuster screw so that it is on one of its "flats" you can feel this as the adjustment gets tighter, it feels hard to turn over the high spot on the screw then when it rests on the adjuster screw "flats" it will wiggle back and forth slightly, this is where it needs to be.

With the shoes locked and centralised back off the adjuster till there is a slight drag on the wheel, do both wheels and now adjust the handbrake cable to suit.

When adjusting the handbrake ensure the wheel drag remains the same as before, the handbrake having no influence on the wheel setting. Set it so there are maybe three or four notches before it locks the wheels. 

[Tornado99]

Weef: Thx for the detailed steps. The advice on the adjuster flats & wiggle is something good to know and I have not seen it called out previously. 

 

If I attempt to replace the forward single cable, Haynes states to have a helper to hold the nuts underside of the pass-through bracket while undoing/re-tightening the bolts from inside the car. Is there a tip or trick to doing that single-handed? 

[weef]

Wire brush up the threads of the screws on the underside to clean off any paint or mastic debris and apply some easing oil. Grip a nut with the biggest pair of self grip wrench that fits on, you are relying on the weight of the grip to overcome the turning force of the screw. Undo one screw completely and remove it and only undo the other maybe half way,or just enough to force the cable through or swing the plates to the side. To refit use a slightly longer screw for the one you removed and feed it from the underside into the cabin. The mastic on the plates should hold it in place enough to allow a nut to be fitted. Reposition the plates tighten the half slack screw, relying on the self grip wrench to hold the nut, it does not have to be super tight. For the other screw hold the exposed length of the longer bolt with the self grip wrench and tighten the nut. 

[Tornado99]

OK test driving today after last adjustment and new adjuster bolts/adjuster blocks and HB lever actuators....good HB braking force at around 2 clicks, three for steep hills. Have to see how long this lasts....I had this performance soon after the last round of adjusting, no more than 2000 KM's ago. How often should I expect to tweak those shoe adjuster bolts? 

Edited by Tornado99, 15 June 2021 - 11:09 PM.

[GraemeC]

Do you have one fairlead plate on top, or one on top and one underneath?

If just the one, it is easier to replace the nut and bolt with spire clips and self tapping screws.

[Tornado99]

Do you have one fairlead plate on top, or one on top and one underneath?
If just the one, it is easier to replace the nut and bolt with spire clips and self tapping screws.

Unsure what is there have not looked closely at it.