Jan 202014
 

It was frustrating to have gone through the process of re-plating/re-chroming all the individual components and to have rebuilt the handbrake, only to find that the ratchet had been butchered to fit an incorrect cable. Rather dispirited, I decided to keep the rebuilt handbrake as is and reuse the offending cable.

I’d hoped that it would be possible to rig up an alternative method of mounting the handbrake switch. However I wasn’t able to come up with a solution that I was happy with. Plus I’d found a number of forum postings of issues setting up the handbrake mechanism even with the correct, unmolested parts.

Old & New Clevises Correct cable is shorter

The existing cable was either incorrect for the car or a poor reproduction part. Both of its clevises were far too long, resulting in an inner cable length that was over 1/2″ too long.

I’m fairly sure that a previous owner/garage had relocated the cable abutment on the ratchet about 1″ rearward as a bodge to compensate for the oversized clevis.

The knock-on effect is the distance between the outer cable abutment on the ratchet and that at the handbrake compensator mechanism on the IRS has been reduced by the same amount. Squeezing the outer cable into this shorter distance effectively reduces the overall inner cable length by 1″ – so a net shortening of approx. 1/2″.

The handbrake compensator offers some adjustment to cater for stretching of the cable over time. Even so, 1/2″ would almost certainly put it at the limit of its adjustability. I’d probably be on a losing wicket trying to get it to work correctly. It was better to bite the bullet now rather than later. So a correct cable was obtained from the Jaguar Enthusiast Club, who now offered them via their online shop.

RM & J Smith were able to supply new ratchets which came as a relief, so it wasn’t necessary to buy a complete new handbrake. The only obvious difference is the pivot bolt spacers are welded to the replacement ratchets.

The fitting of the new ratchet was a simple task but the completion of the handbrake was foiled yet again. The bore of the outer cable abutment was 1/32″ smaller than the 3/8″ cable diameter. It has a slot machined into its circumference and is designed to allow a slight expansion, so I didn’t think anything was amiss.

The bolt securing the switch bracket then clamps the abutment onto the outer cable.

The only way I could get the outer cable into the hole was by continually twisting and pushing it. It didn’t feel right the more I progressed. Considerable effort had been needed just to get the cable half way home. So I decided to remove it and have a re-think. It might be possible to re-drill the bore although I was concerned the slot might cause problems.

I needn’t have worried. As soon as the cable was twisted in the reverse direction, disaster struck …. one half of the abutment fitting snapped clean off.

Aaaaargh and much cursing of repro parts!! Another case of what I now refer to as the Restoration March …. 1 step forward, several back!!

Looking at the fracture, it appears that the whole ratchet is hardened during the manufacturing process, presumably to provide the necessary hardness in the ratchet teeth. The downside, as I found out, is it makes the part brittle and prone to stress fractures. Not ideal for clamping parts which need a degree of ductility, such as the cable abutment.

RM & J Smith have been an excellent source of difficult to find parts and, to their credit, were very good, offering to send out a replacement immediately free of charge. They had identified the problem with the size of the hole and returned the ratchets to their manufacturer to be corrected. I had received one that slipped through the net. The following day the replacement arrived and it fits perfectly.

Getting the warning light switch properly set up proved to be much trickier than I’d anticipated and quite frustrating. The switch is activated by a ‘S’ shaped spring striker. When the handbrake is fully released the protrusion at the base of the lever presses against the striker, which in turn depresses the switch.

The main problem was mounting everything far enough forward so there was sufficient pressure on the striker to operate the switch.

Both the switch and striker are mounted to the bracket by two locking half nuts. So there is very little fore and aft adjustment that can be made. Mounting the switch progressively nearer to the striker starts to pre-engage the switches’ plunger, making the switching more hairpin-like until ultimately it’s permanently on.

I finally got it set up and working on the bench although I still wasn’t 100% happy. The switch had to be angled slightly and the warning light would be on as soon as the lever was moved off the end tooth of the ratchet. The plan was to mount the pre-built handbrake and switch but much to my dismay, I’d completely missed that fact that the cable has to be fed forward into the cabin through a guide bracket in the transmission tunnel.

All the set up was then lost, as the handbrake switch needed to be removed to free the cable. In situ, it wasn’t possible to reproduce as good a set up as before because the floor pan was stopping the angling of the switch. I found the best fit to mount the ‘S’ shaped striker horizontally.

I’m tempted to add some packing washers between the striker and bracket to allow the switch to be moved forward slightly. I think I’m going to leave the fitting the central console until after its first MOT so I’ll still have access to the handbrake.

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