Less expensive TC front brake improvement

3 Jul

Steve Priston now has twin leading shoe front brakes on his TC using a Morris Marina backplate as a template to alter his TC backplates ….. and just a few other mods!

Over to Steve……

“I have recently fitted the twin leading shoe front brake upgrade onto my TC and I must say I feel that it was well worth all of the work involved, I can’t make claims about it being worth the expense because it wasn’t at all expensive, just time consuming, as well as requiring the services of a good welder, one of whom I am lucky enough to have as a very good friend.

My trade is as a mechanical fitter, currently working shifts over weekends and nights, so during quiet times it has been almost therapeutic, having a project like this one.

I first needed to find the most modern vehicles that I could, employing a nine-inch front drum brake, this turned out to be the Girling set-up, as used on a Triumph Toledo, Vauxhall Victor & Morris Marina 10CWT van or pick-up.

Source of supply was of course eBay, where a set of NOS (new old stock) wheel cylinders are to be had for as little as £20, shoes at £10, return springs £6.75, along with 22.5mm long shoe springs, cupped Girling type washers, 42mm hold down pins and Ford Fiesta spring clips; the adjusters are replicas made for a Willys Jeep at £12 a set. It even turned out that I could use the original TC hoses.

What made the job less daunting, was the purchase of a set of TC back plates and most importantly, the luck of finding a NOS offside brake plate, for a Marina van, at a hefty £28!

Above: The lucky find of a NOS offside backplate, stamping number 64276625, from a Marina van. Below: an alloy alignment dolly was made to centralise it with the TC plates, it being turned around, to give the opposite side/hand.

The Marina brake plate was my template/drilling jig, to ensure correct position of each of the critical components, with all of the positions being transposed onto my back plates, simply reversing the plate to give the opposite hand.

All of the holes were filled that were no longer required and a very important modification had to be made to the lower part of the back plates, to enable the lower shoes to fit. The Marina backplate is quite an intricate piece of press work for 10-gauge steel, so care needed to be taken in altering the plate without losing rigidity. This was done by only removing the minimum where needed and replacing what was removed with a very closely fitted piece of folded metal; this avoided any distortion issues on welding, unlike another article I have seen, where this was not done, causing problems.

The important modification referred to in the text.

Unlike a conversion using TD/TF parts, that has previously been featured, I did it the way it was fitted to the intended vehicles, but having been trained in bench fitting at 16 years old, with a few years’ experience since, knew the importance of accuracy, when it came to making the various blanking pieces fit, with minimal clearances so as to avoid distortion during the welding process.

Thanks to the skill of my TIG man, I had no distortion to deal with and very little cleaning up to do.

This picture shows the modified TC back plates, prior to blasting & painting, having had all of the redundant holes filled, wheel cylinder spacer plates attached, the brake spring anchor plates along with the re-positioned brake shoe guides, it also shows the holes for the Jeep adjusters, along with the holes for the shoe hold down pins.

The wheel cylinders needed to be spaced off of the back plate with 5mm packing, the small plates next to them are the spring anchor points, the triangular shoe guides were carefully removed, being re-attached in new positions.

The shoes required quite a bit of alteration, firstly being too wide, requiring one eighth of an inch taken off each side, after the original linings were carefully removed & responsibly disposed of.

The shoes already have short slots for the hold down pins but these needed extending towards the underside of the linings, by about the same length again, another job was to attach a pair of one sixteenth of an inch-thick spacer plates to the trailing end of the shoes, for a better fit in their tracks.

The shoes were relined using a modern woven, brass wire reinforced material, which I know works well on vintage motorcycles with steel brake drums, which turned out to be the single greatest expense, at £50.

The adjusters needed a bit of head scratching because a flat area is required around them on the back plates so new bespoke 8mm pins were made & fitted to the shoes for them to act against, simply using modified bolts, with two nuts.

The Willy’s Jeep adjusters give a movement equivalent to the lining thickness and I chose not to use spring washers, with the plain nuts as supplied but used dowty washers, with stainless nylock nuts, in an effort to prevent seizure through corrosion, by sealing the area of thread within the nuts, having of course copper slipped them on assembly.

One of the wheel cylinders from each side (Girling 64678875/6 or 64676115/6) required the three eighths UNF tapping on its inner port, increasing to seven sixteenths, enabling the TC hoses to fit. If using NOS cylinders they may be a bit grubby outside but the length of time spent on the shelf will require them to be stripped and cleaned as a matter of course.

What I have now is a floating, twin leading shoe assembly, which gives very good feel, being nicely progressive and powerful, rather than feeling like a piece of wood is being pushed against the inside of the drum, it is also lacking the unsightly/costly plumbing as used on the TD/TF, being pretty easy to bleed, with very accessible adjusters.


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