Handbrake MOT fail

[dogs_bolx]

Hi Guys!

Well, its always been a pain, and it appears the handbrake is always poor, but mine's failed its MOT at last! Any tips on getting it though?

ere's what I've tried so far:

Replaced the hand brake pads.
Checkedthe cable pulls both sides and calipers move OK/freely.
Adjusted the screw with the split pin in.
Used the barrel adjuster on the cable to take up any slack.

The pads just dont seen to bite, even though the handle is lovely and tight with no stretch or slop in the cable.

Any ideas? I really need to get it passed. Thanks, martin.

[Guinney1971]

I was once told that you need to adjust the pads in so that they are gripping on the disc even when the
handbrake isnt on, then when you pull the handbrake up they will bite even harder.

Sadly, the DeLorean handbrake is totally cack - or it certainly is by MOT standards - my car usually fails
every year on it :roll:

[dogs_bolx]

Yeah I've tried that, and if it binds a bit they fail for that too!!

I've had the pads so close that the handle is really tight. You can't pull it up barely past 1 or 2 clicks, but the braking action is so weak still.

Any more tips on a resolve so I can pass the MOT?

Thanks, Martin.

[Rich H]

Quote:I was once told that you need to adjust the pads in so that they are gripping on the disc even when the
handbrake isnt on, then when you pull the handbrake up they will bite even harder.

That'd be me then :wink:

I'd suggest it's corroded/seized cables

Are you sure they're free?

You may find the handbrake moves the cable a little bit but will jam up at just the point where the pads should grip, giving you the impression they're working.

Disconnect the cable from the brakes at both sides together, then pull up your hand brake. It should ratchet all the way up to the top of it's travel without jamming. You should see the cable pull in at the brake ends by a good two inches.

I'm guessing it won't and your handbrake will jam up after just a few clicks.....

[dogs_bolx]

Yeah it probably was!! thanks for the Rich, I'll try that and see how well it moves. If i slacken the cables a lot im sure the handle moved about 5-6 clicks...how many should it have in it's travel?

Speak soon, Martin.

[Rich H]

I couldn't tell you for sure, but the handbrake shouldn't go tight at all when disconnected from the pads.

It's easy to believe it's freely moving, when all your actually doing is tightening the length of cable up to the bit that's corroded.

[Nick H]

I have been doing a refurb on LJH's rear brakes. The car has always had a marginal handbrake.
While I had the calipers off I decided to have a good look at the handbrake.

There is not a lot of info in the factory manual. However there is a gem of information that the handbrake calipers are self-adjusting and operate via a racheting pawl. This is inside the arm that has the handbrake cable attached to it.
As this the same set up as the earlier XJS's have. I did a bit or research into these. I found that the XJS can suffer from the same dodgy handbrake as our cars. This is not down to the cables in most cases. It is failure of the self-adjusting mech. in other words the racheting pawl.

The quick fix which also applied to the XJS is to tighten the cables up. This is only a temp. repair.

First remove the hand brake caliper from the car.
To get at the Pawl you need to remove the split pin from the top of the arm and using a drift/pin punch drive out the
securing pivot pin. Then remove the screw from the cover. The cover then comes off. You can then see a spring holding a thin spring steel pawl that is engaged in a splined nut (sure it has a proper name).
Chances are that the spring steel pawl is stuck/rusted to the inside of the arm. Once you free this off, cover it in spray white grease. Check the splined nut is not stuck.

Put it all back together. When you replace the pads turn the shaft that goes into the splined nut this speads the caliper. When you put the caliper back on the car clean the bearing faces and put some copper grease on them to stop it rusting/sticking. Put some more on the plain part (non threaded) of the bolt/pins that attach the handbrake caliper to the main caliper. Put a dab on the end off the brass spring pins that locate in the top of the handbrake caliper.

When you have it back on the car move the arm away from you i.e in the direction the handbrake cable pulls. You should see the pads move in and stay. You may also hear a click of the pawl engageing. Repeat this until the pads
just lightly touch the disc. Then you can adjust the cable for the handbrake. Which will probably need slacking off.

I reckon I can now hold the Queen Mary on that handbrake now

Hope this helps someone out.
Regards
Nick H

[Guinney1971]

great stuff Nick, this could well be worthy of a tech article in the mag
if you can send it over to Eddie

[Rissy]

This sounds interesting, but without photos, and big red arrows, i'm having a hard time imagining it all. Especially since I have no idea what a "pawl" is lol!

So, yeah, a tech guide would be very good indeed! Go for it Nick!

(of this "pawl" part is the metal housing you can remove from the car, with a spring inside it, then i've had both mine off the car and used lots of oil etc to try to loosen it off in the past. Perhaps i've just not done a good enough job. Al though saying that, i *think* my hand brake is now working after once again spending more time on it at the tail end of summer last year. Been garaged ever since though, so still to fully test on the M.O.T tester for the numbers....)

[Rich Hanlon]

Sounds interesting stuff, mine has always been woeful too.

do you have a link to the XJS source you got this from at all?

[Nick H]

When I get a bit more time I will try and write a how to guide. I did a online search and found this exploded diagram of the calipers. This gives quite a good guide on how they come apart.
http://www.2carpros.com/questions/jaguar...eplacement
A pictures worth a thousand words and all that :wink:
Regards
Nick H

[stunned_monkey]

dogs_bolx Wrote:ere's what I've tried so far:

Replaced the hand brake pads.

If you used cheap ones, they are probably worse than the originals.

[Guinney1971]

we got some from Halfrauds for 'Sorbet', was about £24 for a set.

X-ref'd to a mid 70's Jag XJ6 3.4, took 24hrs to come in.

Cant remember what make they supplied though, it was a couple
of years ago.

[Rissy]

I got replacement handbrake pads for Lexi in 2010.

This is where I got them from, and they've done me fine until now (probably because the Bl**dy thing doesn't work most of the time!), but am planning on buying another set for continued mucking around with the whole Handbrake system to try and get it working properly if it still fails at the M.O.T later this year.

http://britishparts.co.uk/products/7749 ... ke-JLM1514

[bjbrownie]

One thing to check which was at fault on mine, is the handbrake bracket which the cables pass through- I fitted new pads (British Parts) and after adjustment per manual still couldn't get a good handbrake action, especially on the passenger side wheel. Close inspection of the handbrake bracket showed that the repeated action of pulling on the handbrake hard had actually pulled the cable mounting 'in' towards the handbrake itself,losing about 1/4" of movement, not surprised that it wouldn't work properly.
I removed the handbrake assembly, straightened the bracket with the knocking tool, and found 2 large 'penny' washers to reinforce the area where the cables entered the bracket, tightened everything up and it worked perfectly, 4 clicks on the lever locks both wheels solid, and a good result for brake effort at the mot-and it's been no problems handbrake side for the past 7 years! 8)