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Lockheed Self Adjusters and Handbrake Function  Rating:  Rating
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 Posted: 01-23-2016 07:02 pm
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NigelK
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Dear Forum Users

The handbrake on my GT has never worked very well, even with the clevis on the handbrake cable adjusted to its tightest setting. I did some research online, particularly on TR7/TR8 forums (as these cars share the same Lockheed drum brakes), and it seems in many cases poor handbrake function is actually caused by a problem with the brake shoe self-adjusters, which, er, don't...

There are a number of steps to making the self-adjusters work properly.

Firstly, they need to be installed correctly. Figure F4 in the J-H WSM is completely wrong - the self adjuster pins should be inserted from inside to outside, such that the pin flange is on the inside face of the brake shoe web. The two self adjuster levers also sit on the inside face of the shoe web, with a small shim washer between the self adjuster lever and the brake shoe web. The upper lever also has a spring between the adjuster pin flange and the lever itself. On the other side of the brake shoe web i.e. the outer side, a thicker washer should be placed over the upper adjuster pin, and then a circlip. The lower adjuster pin only has a circlip.



Secondly, the mating surfaces of the self adjuster levers and the brake shoe web should be rubbed down so they're completely smooth, and lubricated with high temperature grease. Check that both levers move smoothly across the face of the brake shoe web before reinstalling the brake shoe.



Thirdly, make sure the serrated teeth on each self adjuster lever are free of rust, I used a wirebrush. If they are worn, it may be necessary to gently sharpen each serration with a hacksaw blade. I didn't have to do this. Apparently, the geometry of the teeth is such that the lower adjuster lever can only adjust in one direction, so you may need to use a magnifying glass to make sure you're sharpening the teeth correctly.



Fourthly, disconnect the handbrake clevises on both sides before installing the brake shoes and checking the brake shoe adjustment. Pulling up the handbrake 4-5 times does NOT adjust the self adjusters, as is stated in the Haynes Vauxhall Magnum workshop manual (and repeated elsewhere). Connecting the handbrake actually stops the self adjusters working during the brake set up procedure. Pushing hard on the brake pedal, with the handbrake clevises disconnected, is what makes the self adjusters adjust. If everything has been assembled correctly, and the self adjuster levers can move freely, you should be able to hear the self adjusters click when you depress the brake pedal. If this doesn't work, the self adjusters can sometimes be persuaded to adjust by reversing quickly, and stamping on the brakes. But if you do this, of course, you won't be able to hear the self adjusters adjust.

Finally, once the self adjusters have adjusted you can reattach the handbrake clevises and adjust the left hand clevis so that the handbrake functions properly.

Using the above steps, I now have a working handbrake. It only took me 2 months to work it out...

I hope this is helpful for others having the same issues that I did.

Best wishes,
Nige

Last edited on 08-15-2017 08:43 pm by NigelK

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 Posted: 01-31-2016 10:04 am
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NigelK
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Bump. Photos added

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 Posted: 10-30-2016 02:51 pm
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Bfitz241
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Thanks Nigel. Just did the rear brakes, this was a big help.
If I may, I'd like to add that if the wheel cylinders are frozen the adjuster will not back off. I'm sure you've figured out how I know that.

Last edited on 11-25-2016 02:39 pm by Bfitz241

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 Posted: 03-11-2017 04:55 pm
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NigelK
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Despite the self-adjusters working properly, I have not been able to get my handbrake to work since the LSD axle was installed. What happens is that the handbrake lever pulls away (moves inboard) from the web of the leading shoe on the left hand rear wheel when I use the brakes. Or the shoe moves outboard from the lever. Either way, the notch on the handbrake lever is no longer engaged with the leading shoe so when I activate the handbrake, the lever moves forward but the notch in the lever does not engage with the leading shoe web, so the shoe is not pressed into the drum which means the handbrake cannot function.

The handbrake works fine until I drive the car and use the brakes, then it stops working. It would seem that when the wheel cylinder pushes the shoes against the drum, something is not aligned properly so the shoe web does not re-engage with the notch on the handbrake lever when the brake pedal is released and the shoes return to "home" position.

I am going to replace the handbrake levers (assuming I can find some), as maybe the notches in the existing levers are too worn. And also replace the pull-off springs, steady pins and springs, the wheel cylinders and circlips. Maybe that will stop the leading shoe moving relative to the handbrake lever. Anybody got any other ideas?

Best wishes,
Nigel

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 Posted: 03-17-2017 07:14 pm
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NigelK
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Sorted. Today I replaced all the moving parts plus the wheel cylinders and the handbrake now works properly. I think the key issue was a distorted circlip, which was not holding one wheel cylinder securely to the backing plate, so when the brakes were applied the cylinder was pushing the shoe away from the backing plate, disengaging it from the handbrake lever. Fingers crossed that the handbrake keeps working!

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