Lotus Elan

Elan Cr**P handbrake

PostPost by: bloodknock » Sun May 12, 2013 6:20 pm

Hello peeps
In the dim and distant I remember the hand brake on my sprint, and indeed on two other Elans I owned, driving me and the MOT testers crazy.
I am now rebuilding the sprint and seek the wisdom of the oracles on this website. I have had the calipers rebuilt professionally (dont remember who, it was 20+ years ago) but the whole assy of the handbrake is very sloppy and the adjusters seem pretty ineffective. I am only just assembling them onto the chassis, and would appreciate real guidance in making them effective or even improving them.
Cheers
Bob
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PostPost by: Quart Meg Miles » Sun May 12, 2013 8:37 pm

I fixed my S2 handbrake when Prince Charles married Diana (1980 and 100,000 miles ago) and have never failed an MoT through it since. I can even tighten (bolt-on) wheel nuts against the handbrake with the wheel in the air. The caliper bits are original and pretty loose but the adjusters work fine.

Remove all the pins in the tree assembly (Chassis Mounted Fulcrum in manual section J fig 14-15) and drill through the tree and all the cable or rod U ends so that all holes are circular again. Similarly the outboard caliper to rod connection. Then turn new pins with just 0.001" clearance and assemble with copious grease.

In the absence of lathe facilities or willing local machinists you can make the pins from standard stock rod with some filing (in a running drill chuck). To keep the pins in place just cross-drill holes at both ends to take standard clips or stiff wire.

The crude "springs" holding the pads back have to be fettled the hard way: removing them, bending them appropriately and refitting them until the pads are held back equally when the handbrake is released and the adjuster slack. Perhaps someone else has a slicker method but they don't need much attention once done.
Meg

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PostPost by: bloodknock » Sun May 12, 2013 9:11 pm

Thanks, you give me more confidence.
Ive made up some new adjustable length rods from the tree to the calipers with rose joints on the ends. Ive made sure that the tree holes are round and a snug fit to the rose joint ends. Its the actual calipers i'm worried about, there seems to be a lot of slop in the main fulcrum joint. Perhaps I am worrying unduly and all will be well when I finally connect it all together. Also, the ratchet mechanism spring form seems slack in that the ratchet turns very freely. Is it possible to buy new spring forms?
Regards
Bob
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PostPost by: john.p.clegg » Sun May 12, 2013 9:13 pm

Bob
You could fit a later tree,search the forum and you should find the dimensions..

John :wink:

P.S.

lotus-suspension-f42/hand-brake-tree-t20972.html
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PostPost by: billwill » Sun May 12, 2013 10:40 pm

Two main things are needed to get reliable handbrake caliper function.

As mentioned above the little lifters that lift the pads off the disk, need to be reshaped outwards each time new pads are fitted. They are not very springy and indeed may have been designed that way so that they bend in as the pad wears thinner, so that they do not apply too much lift.

Secondly they need to be helped to get the pads consistently off the disk, by putting a coil compression spring on the adjusting rod, between the two calipers. Not a strong coil spring, something which takes about 2 to 4 pounds to compress.

If you don't do these two things the handbrake pads will wear fairly rapidly as they will tend to touch the disk.

The top 'bearing' does need to be a bit floppy, I think, so that both pads list off by roughly equal amounts.

The clearance between pads and disk when properly adjusted is very small, barely the thickness of a postcard.

The clearance needs to be adjusted fairly frequently (in the UK just before each MOT test :wink: ) but you can usually tell by how far the handbrake lever pulls up in the cabin. Ideal is only about 3 clicks of the 'umbrella handle' ratchet.

~~~~~~~~~~~~

I don't know where you can get replacement caliper ratchet nut holding springs, I've wondered whether they could be de-tempered by heating to red heat and cooling slowly, then bent inwards & then re-tempered by heating until they 'blue' and then dunk in oil.

Attempts to bend without de-tempering, will probably just break off one of the spring leaves.

Maybe Classicar Automotive can supply these nut springs.
Bill Williams

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PostPost by: EPA » Mon May 13, 2013 11:27 am

As others have said the centralising strips are all that keep the pads away from the disk when the brake is off and must either be bent back to the original shape or replaced with new ones when fitting new pads or the new pads will wear very quickly. The other thing I found (mine is a +2) is that the main arm of the tree should be as close to 90 degrees to the car as possible when the brake is on.This gives the maximum leverage but also one of the smaller arms of the tree can end up pushing against the diff case if it is too far forward with the brake applied(this was the case on my + 2)
The handbrake on my +2 will now lock the wheels on the MOT rollers and I test it on a steep hill nearby and it will hold the car easily.

Good luck
Ed
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PostPost by: types26/36 » Mon May 13, 2013 3:38 pm

bloodknock wrote:the whole assy of the handbrake is very sloppy .Bob


The arm on the calliper where the clevis pin goes through has a small bush/spacer in the hole, if this spacer is missing you will get slop in the linkage and lost movement.
Check to see if it is still there and if missing you may have to make them up.
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PostPost by: oldelanman » Mon May 13, 2013 4:33 pm

EPA wrote:This gives the maximum leverage but also one of the smaller arms of the tree can end up pushing against the diff case if it is too far forward with the brake applied(this was the case on my + 2)


Check that the spacer on the pivot bolt is fitted in front of the compensator and not behind.
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PostPost by: Quart Meg Miles » Mon May 13, 2013 9:15 pm

types26/36 wrote:The arm on the calliper where the clevis pin goes through has a small bush/spacer in the hole, if this spacer is missing you will get slop in the linkage and lost movement.
Check to see if it is still there and if missing you may have to make them up.

You're quite right, it's not like the tree, and I had a pair of bushes made in 1973 but the real handbrake cure was eliminating the teardrop holes in the tree linkages.

John,
Bob should already have the later tree but there's nothing wrong with my early one since the holes were fixed. It sounds like he's already done the work with his Rose joints.
Meg

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