I might have only gone and solved the Handbrake issue!

[Rissy]

Darren C Wrote:Rissy,

It's satire, and not meant to really offend you, just an expression of my opinion on your post, with a playful friendly putdown.
I do not claim to have discovered a "design issue". Nothing of the sort. We all know how it works. What I have done is analyse the condition and highlight and explain (in detail) what is wrong and how to resolve it.
Granted, others have noticed the angle of the pads, but no-one has posted an informative and detailed resolution.
Yes we all understand the occasional nature of Delorean usage and the
in-frequent use of the handbrake to hold the car when parked. But unfortunately we need the car to meet the MOT regulations and have become complacent with the "Delorean handbrakes are Sh*t" attitude when in fact the problem can be resolved.
I have these exact same calipers and handbrakes on my other cars, and they work well. So they should work well in the Delorean.
The fact of the matter is that most owners have simply given up.

Please just take the picture down. If only out of courtesy and not respect. I would NEVER EVER explode out on someone like that. If people don't understand that I was going through experimentation from what I have written, then I'm sorry. I don't know how else I could have made it clear other than to have used the word "experiment" in there somewhere. My point is that I hadn't given up and i've continued ever year within my limited contact to continue to look into this issue, year after year. I only get a couple of weeks with the car a year, so it's difficult.

I'm slowly learning to not say much on this forum. I have for a while, and been going quiet are as a result. This experience doesn't help.

Good work Darren. I hope you get to the bottom of it all. I look forward to benefiting from your research one day. I'll keep my experiences to myself for fear of ridicule (again).

Please. Remove the picture.

[Darren C]

Rissy,

Again I'm sorry I've offended you. But you never said it was experimentation?

You said "This worked to a fashion, but also tended to put undue stress on the pads and they'd eventually fall apart."
The trouble with Forums is that people can only respond to what you've said/written, not what you now wish you'd said.
From your statement using words like "eventually" makes it seem like a long time, not some short experiment.
As an engineer I completely stand by my reply/opinion on the use of shims, tapered washers and glue being used on a cars brakes (even as an experiment)
Particularly as someone may not fully comprehend and copy you with terrible consequences.

Please share you're experiences, don't hold back for fear of ridicule, I've been called many things in life, far, far worse than my earlier satirical reply to you, and it never did me any harm, I just learnt from it and moved on.

[Rissy]

Being an engineer myself, I like to think that my assessment of things is not slap dash. I always do things with consideration and in the most thorough way possible.

Believe me, the last thing I want to do is endanger anyone's life, especially my own, not to mention risking my car.

I'm not defending myself any more.

[Darren C]

Edited upon Darren's request.

[Rissy]

The shim was in between the caliper and the back side (metal fascia) of the pad. All it did was put the pad at an angle. It was also held in place by the M5 bolt.

It didn't rattle around.

It was held steadfastly in a sandwich between the pad and the caliper, just as a measure to produce an offset angle of the pad.

The problem was that it produced an angle where the flat of the M5 hugs the inside of the pad which was harder for me to compensate for (but I did try). I tightened up the M5 bolt so that it held it all in place right but because of this angle, when the pressure from the hand brake was applied, it slowly tore the flat from the end of the bolt.

I played around with this idea for 2 days a couple of years ago. Taking the wheels on and off all the time to check the pads and their condition after driving round the block just to get to a steep hill for holding trials, nothing more.

The pads were never gripping a spinning disc. Only a static one. It's a hand brake not a foot brake. Besides, the car never got past 10mph driving round to the hill I used to test the solution.

However, I knew there was an issue which I realised would not be good for anyone, but it was at least learning another way it can't be resolved. This is why I've reverted to slowly bedding in my pads and have been at that for the past 2 yrs.

I'll keep myself to myself from now on. I'm clearly the next person losing interest in staying on this forum because of people's attitudes and personal insults.

You've made your position clear with refusing to take back the muppet talk, so that's fine. I'll bid you good day sir.

Oh yeah, and I'm a bloody good engineer I'll have you know. I don't take risks lightly. I always used a slowly and considerate and careful approach. Not slap dash as you keep insisting.

[Chris P]

I wish you would both calm down.

There have been some interesting options offered and I personally think we should leave it there.

Ex mechanic …not an engineer…..with the back brake callipers currently stripped down on my RAV 4!

[Guinney1971]

whilst I dont approve of the muppetry talk or tone of this discussion in places,
its certainly been an interesting one, and something I'll be discussing with the
garage I used when 'Flopsy' goes in for some suspension work soon (MOT due
early May).

The pads in my car are a couple of years old, and are Jag XJ 3.4 that I got from
Halfrauds for about £22

[Darren C]

Thanks to those of you who have telephoned me to discuss the Handbrake operation and offer more questions than answers!

What seems to be consistent is the lack of documented instruction on the Delorean handbrake setting and general workshop information. Not surprising really due to historical circumstance of DMC.
So I thought I’d look at what books I have stashed away for my other cars using this Girling Caliper, and see what I could find.

The easiest to find and most common source of information is from Jaguar/Daimler.
They fitted this calliper (in it’s earliest Dunlop incarnation) from around 1957 (post XK150 cars) Then updated to the Girling version with the E-type & XJ series of cars.
Picture below from my early XJ manual



I cross reference this with a very hard to get hold early 1970’s Aston Martin Newport Pagnell Works Manual and can offer two answers to some of the questions I’ve been asked.

Question 1

“How many clicks of the lever are acceptable when adjusting the handbrake cable, and when do I need to adjust it?”

Answer.

“3 to 4 clicks to maximum handbrake operation. 5 clicks or more and you need to consider adjustment”.

Source of the above

Handbrake adjustment Aston



Handbrake adjustment Jaguar/Daimler



This is as close as I can get to a definitive answer and not hearsay or urban myth. Some may argue that it depends on the ratchet teeth spacing and fulcrum lever measurement, but believe you me the Jaguar/Daimler lever is completely different to the Aston one, so in the scheme of things it’s a pretty good guess at answering the question.

The next question was quite interesting (Well I thought so in my OCD kinda way)

Question 2

“When do I know when to change my Handbrake pads?”

Answer

“At a pad thickness of 3.175mm or 1/8 inch” (Unless damaged or contaminated with oil/fluid)

Source of the above

Handbrake pad replacement



As stated earlier this is an identical Girling calliper & Handbrake mechanism using the same thickness disc of 12.7mm new, and the same Handbrake pads, so it’s fair to assume that the wear data is correct.

Hopefully this will help clarify some of the ambiguity and prove helpful.

I also have a theory about the stretch of Delorean handbrake cables when under load, so watch this space as they say whilst my quest continues!

[Darren C]

Another symptom that has been considered is that the return forks are known to break or loose their spring tension. With new forks and a correctly set cable it should be possible to ensure the pads dont drag. The other Girling book I have says that when you have rebuilt the calliper off the car, set the gap between handbrake pads at 3/4" or 19mm with the sloted screw, insert split pin, fit the calliper back on the car and before you connect the cable, move the lever/arm back and forth to operate the ratchet adjuster until it clicks no more, then you should have a clearance of 5 thou between pad and disc. (if the internal adjuster is working of course)
Providing the return fork has a good spring and your cable has its slack taken up only, then in theory the pads should always stay clear. In reality what seems to happen is the cable pulls the arm ever so slightly and drags the outer pad. This is most probably why people need to re-adjust each year before MOT.

[Rich Hanlon]

A feature that seems to have the same effect as the cable stretching is that the rearmost plate on the handbrake bracket is pretty thin and The tension on a tight cable is sufficient to bend it. This is the plate that the sheathing of the cable acts against - ie it is what reacts the tension in the cable. It means that some of the effort from the lever is actually going towards bending this plate rather than operating the 'pincers'.

Last year I plated this up with some stronger stuff and shortly afterwards somebody else on here came on and said they'd done the same - bJbrownie perhaps?

It had some benefit but glad that we seem to be getting towards a solution here!

[Darren C]

Yes. Thanks, good point Rich.

It was Brian who noticed this and posted a picture of the re-inforced cable mounting bracket under the handbrake. This is a good find and I am currently looking into this along with the cable inner and its sheath as an age related defect that may be part of the issue. However I am very confident from my findings on the pad to disc contact as the main culprit, with the benefit of MOT test roller results, old pads, new pads and "fitted" pad readings; matching the pad angle and face contact gave a 100% improvement than pads that had been in the car over 8 years, and 400% improvement on pads straight out the box!

[jwrayth]

Rich Hanlon Wrote:Last year I plated this up with some stronger stuff and shortly afterwards somebody else on here came on and said they'd done the same - bJbrownie perhaps?

That'd be me, I believe. My hand-brake failed after completing a drive to Scotland, and upon taking out the drivers seat I found the bracket rusted and bent at the rear. Re-shaped it, sanded it down and welded on a thick steel plate to re-enforce it.

Then back in Feb this year I replaced my damaged hand-brake cables (along with correctly routing them to avoid further damage, that the P/O had neglected) and re-adjusted my callipers. Didn't change the pads out though since they had plenty of grip and width on them at the time... and I'm thankful having read the revelations here!

Sounds like I'm currently owner of a rare DeLorean; One where the handbrake still works long after fixing it for the MOT!

[Darren C]

Well done on sorting yours out. Again it seems that when you fixed your cars particular fault and adjusted correctly the mechanism the old pads that were presumably bedded in worked a treat.

Tonight I thought I’d take a look at the Handbrake Bracket



If you haven’t seen it before, the handbrake cables locate in the two holes, one above the other in the bottom left of the bracket above.
As previously stated by several owners this bracket is prone to bending.
From its design you can see that the folded end where the cables locate is only supported on two sides (the top & right side in the image above).
I agree entirely with what has been said previously; this is a weak point.
However I needed to test this so tonight I investigated further to gain a definitive answer.
Upon folding back the carpet in my car I revealed the rear of the bracket and cables. My particular bracket is very slightly bent (not too bad, just a small visible dishing of the end plate), and I would think that this is quite common amongst our cars.

Ok, so the only way that the bracket can bend is if the handbrake lever is operated and all movement is taken up at the wheels and force is continued to be applied.
But what if this bracket is flexing and causing loss of tension in the handbrake under NORMAL use?

I needed to measure this some how.

Having pulled the handbrake on and off several times while watching the rear of the bracket and cables I was convinced it was yielding.
I set up my DTI (Dial Test Indicator) which can measure ½ of a thousandth of an inch movement on the bracket as close as I could get to the cable location point, then zero’d the indicator



I then pulled as hard as I could on the handbrake lever. The cables move as they take the strain but the bracket in reality HARDLY moves at all!



Total deflection with tugging on the handbrake lever far more than you would in normal use gave a 4.5 thou yield of the bracket.
This is no where enough to cause a permanent poor handbrake.

I can only conclude that the brackets bend over time ONLY when extremely excessive force is applied to the lever, and under normal circumstances are fit for purpose.

That said, I would strongly recommend that owners check, straighten and strengthen or replace any damage brackets.

Once bent however, it is fair to conclude that if the slack is taken up in the cable to compensate for a slightly bent bracket, the handbrake operation would be regained and unless the owner had checked the bracket they wouldn’t know its bent. Excessive force would obviously continue to bend the bracket further.

I agree totally that this is a contributory factor in poor performance, but have proven the bracket only to yield (by such a small amount) under more force than would be reasonably used; to say that this is NOT the main culprit.

[Rich Hanlon]

Amazing detective work mr. C!

[Chris Williams]

Well it seems I have found why mine are no longer working :roll: As I had mentioned before I had intended removing the handbrake calipers to be refurbed as these were the only parts of the braking system that were not new or refurbed when the car was put back on the road last year after it's 14 year lay-up. I had installed new pads supplied by a Jaguar specialist (part GDB709C pads XJ/XJS Copy) and set them up so they worked, anyway as I had mentioned in an earlier post they were no longer working at all. Removing them this morning to send them away I can now see why. Two of the pads had gone, don't know when or where but they had unstuck themselves from the mountings one on each wheel. (as had happened to Rissy I think) None the less when the new ones are returned from Wards I will measure the pads and report the findings.
[ATTACHMENT NOT FOUND]
chris