Lotus Elan

Blasted handbrake mechanism!

PostPost by: MarkDa » Sun Apr 12, 2020 10:30 pm

I ran my Sprint without returning springs for a while many years ago and didn't notice any wear to speak of.
Upon doing my full rebuild a few years ago I put them back in - don't hinder operation.
I too shimmed one caliper to get it central over the disc - this must make sense if the handbrake pads are to hang evenly.
I suspect that the compression spring is important in getting the pads to come off the disc.

Getting slack out other tree and rod linkages is crucial if there's to be enough movement for the pads to clamp.
I put sleeves in the levers to get a good fit around the new (unworn) clevis pins.
Rather than spring for adjustable rods I just cut the end off the yoke and redrilled the holes to gain about 10mm or so.

My hand brake does work but I always put it in gear as well :)
It does just generate enough friction to pass an MoT and bear in mind the test is tougher on single circuit brakes.

The bottom line though is that the 'leverage' in this system is low and more force is needed at the handle than on most cars.

@JonB are you about to start a full rear end rebuild now?
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PostPost by: vstibbard » Mon Apr 13, 2020 5:30 am

I assume the reason for shimming was due to the whole caliper being off centre, not just the handbrake pads.

Did you use hardened washers, if not I would replaced as they will come loose.

Vaughan.
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PostPost by: Mazzini » Mon Apr 13, 2020 5:35 am

I used shimming steel washers made in various thicknesses by my neighbour. My primary concern was to centralise the caliper to the disc.
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PostPost by: UAB807F » Mon Apr 13, 2020 5:54 am

I'm another one who struggled at MoT time with the handbrake. It always looked sloppy and flimsy, something thrown together as an afterthought when someone pointed out "hey, we're going to need a handbrake if we want to sell these things".

A few years ago I decided to re-make it and of course used the Brunel school of engineering, heavy and solid. Rose joints and bolts replaced pins and bushes, adjustable rods and a sweep on the central actuating arm which clears the diff and gives a bit more leverage.

Much heavier of course but rock solid, very simple to adjust and yes, it does work. Extra leverage is nice but I think the biggest contribution is from having adjustable linkages because you can set the movement evenly across both calipers.

http://www.martley.plus.com/lotusland2016/elan/16elan03.html

As an aside, that pad in the first post looks wrong. I've replaced the friction material on mine in the past and the steel carrier has a circular recess roughly an inch diameter and maybe 1/16" deep. There's a hole from the bottom of this recess going through to the other side of the steel so that when you clamp the pad to stick it together, the excess glue comes out the back.

Hence the friction material needs shaping to form a male "spigot" to go into the recess, but that photo looks like it's just a flat pad. If they're all like that, they're going to fail.....

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PostPost by: JonB » Mon Apr 13, 2020 9:23 am

MarkDa wrote:@JonB are you about to start a full rear end rebuild now?


Ha ha, no thanks, Mark! It's already got new bushes and the wishbones got an unwanted lick of paint (by the man who did the bushes - and he charged me for the paint and time without asking :evil: ). Don't forget the diff is overhauled and it's got the CV joints I fitted. So not much to do other than new shocks / springs / lotocones and overhaul the brakes (none of which is needed yet).

vstibbard wrote:I assume the reason for shimming was due to the whole caliper being off centre, not just the handbrake pads.


Yes, it is just visible in the second photo.

vstibbard wrote:Did you use hardened washers, if not I would replaced as they will come loose.


Dunno. Do washers have hardness markings? (Rhetorical - they don't as far as I can see!) Can't see them coming loose - the bolts are wired. I suppose if they squashed out it might happen, but I will keep an eye on the bolts. Can always retorque them if need be.

UAB807F wrote:As an aside, that pad in the first post looks wrong. I've replaced the friction material on mine in the past and the steel carrier has a circular recess roughly an inch diameter and maybe 1/16" deep. There's a hole from the bottom of this recess going through to the other side of the steel so that when you clamp the pad to stick it together, the excess glue comes out the back.

Hence the friction material needs shaping to form a male "spigot" to go into the recess, but that photo looks like it's just a flat pad. If they're all like that, they're going to fail.....


These pads are the only game in town, Brian. The PO actually had material bonded to the existing backing because he said you couldn't get replacements, and this seems to have worked well. I see no holes in the back of the old pads, so perhaps they are wrongly made as well. I'd worry about this, only the handbrake keeps the car still rather than having the job of slowing it down (except in absolute emergencies) so I can always put the car in gear (always do, to be honest). I suppose I should not be surprised at the low quality of these parts. Disappointing though as they cost £40.
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PostPost by: UAB807F » Mon Apr 13, 2020 11:05 am

JonB wrote:These pads are the only game in town, Brian. The PO actually had material bonded to the existing backing because he said you couldn't get replacements, and this seems to have worked well. I see no holes in the back of the old pads, so perhaps they are wrongly made as well. I'd worry about this, only the handbrake keeps the car still rather than having the job of slowing it down (except in absolute emergencies) so I can always put the car in gear (always do, to be honest). I suppose I should not be surprised at the low quality of these parts. Disappointing though as they cost £40.


I have to smile at that, keeping the car in gear was standard practice when I used mine daily, I never trusted the handbrake to hold the car on it's own :wink:

I rummaged through my spares & found a half completed pair of pads which illustrate what I was on about before. On your first photo there's a black dot just about the right place for the relief hole to be and if so, then your pads are probably the same.

Handbrake pad supplies were intermittent years ago and for one MoT I got a fail because the tester thought the lining was too thin. So I did pretty much the same as you have there, ground away the old material & stuck on a new layer cut from an old front disc pad. And of course one side came away, but fortunately after the MoT....

Then when cleaning it up for another go I noticed the recess appear and realised the principle behind the design - with the spigot/socket arrangement the pad doesn't rely on the shear bond strength of the glue to hold everything in place under load. It's a fuss shaping the friction material but once done they last very well.

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PostPost by: JonB » Mon Apr 13, 2020 11:14 am

Contrary to what I wrote earlier, there IS a hole in the rear of the old pad. You can see it in the photo I took.

So perhaps I can do what you did and fashion my own pads, complete with circular spigot thing. Golden rule is, as ever, to not throw old parts out.
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PostPost by: sveris » Mon Apr 13, 2020 4:43 pm

If anyone needs to replace the white push button for the handle, I have 3 left.
$20.00 plus postage.

Steve in Ohio
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PostPost by: Grizzly » Mon Apr 13, 2020 10:15 pm

I spent quite a while trying to master the hand brake on my Elans.......

First thing is replace the pad return strips after every second set of pads, i know they can be bent back but they go soft and don't work properly (the pads end up not being lifted off the disk properly and overheat)

Then i'd suggest setting the calipers up with the rod's disconnected, what you are looking for is min movement off the stop and with the weight on the wheels you want to adjust the cable length until the rod pins just drop in both sides.

As you already known if the hub hasn't been pushed through the bearings properly the disk will be out of wack to the caliper..... if that happens and you try to set it up without centering the disk - caliper you will not be able to get the pads close enough to the disks without binding.

Not a big fan of Mev parts, some stuff is ok but for brake parts i always go to http://www.classicarautomotive.co.uk/ not only do they stock most things for Lotus cars but the boss worked for Chris Neil back in the day so knows all the tricks.
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PostPost by: MarkDa » Mon Apr 13, 2020 10:32 pm

Thanks Grizzly
Now I know why the caliper needed shimming!
We learn something new every day.

I was planning to strip down the hub on that side anyway as there's a bit of vibration.

I'll make sure I get the shaft properly home this time!

Having had my servo remanufactured by classucarautomotive I too can recommend them.
Last edited by MarkDa on Tue Apr 14, 2020 9:37 am, edited 1 time in total.
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PostPost by: JonB » Tue Apr 14, 2020 9:03 am

Grizzly wrote:As you already known if the hub hasn't been pushed through the bearings properly the disk will be out of wack to the caliper.....


Interestingly, the bearings on that side were replaced by me a year or so ago. Maybe I didn't fit them properly. Would it be possible to fix this by tapping the spider a little (effectively, moving the driveshaft outboard)?
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PostPost by: alan.barker » Tue Apr 14, 2020 9:27 am

Jon,
please don't Tap/Hit the Spider you will bend it and it will put micro flats on the Ballbearings inside the Bearing Race. If when you replaced the Bearings you have fitted the big round Dust Sheild on inside Bearing and Circlip. + when you pressed the Bearing onto the Shaft you fitted the inside small Dia Circlip that stops it moving along the shaft it is in the correct position.
Imho if the Disk is not exactly centred in the Caliper it's not a problem.
For the Caliper Pistons one just moves out of the Caliper a little more than the other and stays in it's static position. The Pistons do not return back into the Caliper Body every time you release the Brakes, they just stay in their static position (the seals hold them in the static position).
For the Handbrake Pads they are held in their static position after the first operation of the Hand Brake by the Metal Strips.
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PostPost by: JonB » Tue Apr 14, 2020 9:51 am

Well, my initial testing indicates all is well. I have almost no dragging (there's a very slight noise as of metal against metal, probably the pads "just kissing" the disk surface) and it is way better than before. Then, on application of the handbrake, feels like both wheels are locked. Will know more when I get it off the stands for a test (when the rad fan motor is back in; currently waiting parts). Then I can try to move it using the engine with the hand brake on; the engine being way stronger than me!

I think the advice about the centring strips is good. Mine look pretty dead. Might even be original. They are rusty and one of the little bolts is not tightening up properly. Probably thread has stripped.
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PostPost by: alan.barker » Tue Apr 14, 2020 10:09 am

Hi Jon,
well done.
A little noise of Pads polishing the Disks means they are in the good position.
I think you only need about 20% for the Hand Brake to pass MOT.
For info:
The Run Out for the Disk should be no more than .004" and when there is more it's because someone has bent the Spider on Drive Shaft. Hammering shit out of it when stripping it down. Then the Spiders need resurfacing on both sides in a Lathe. I've seen a broken Disk because the Spider was bent and the braking vibration broke the Disk. :shock:
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PostPost by: JonB » Tue Apr 14, 2020 10:32 am

Good job the drive shaft was replaced then (by me). It's a billet unit from TTR.
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