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TVR Tasmin, Braking Things

In the quest to both right previous wrongs and make things on this car actually work, I had to have a look at the braking system. It worked, kinda, but needed to be better.

Sitting around for a couple of years does no car any good, and the TVR hadn’t had love in a while, so it was anyone’s guess when the brakes were last touched.

The main braking system worked OK, albeit there is a fairly bad pulsating through the pedal when braking. I’m hoping this is due to the rust-covered rotors, and not a sticking caliper. The hand brake just doesn’t work at all; you fully engage it as hard as you can hulk the handle up, and you can still easily roll the car along the garage floor. Not ideal.

The brakes on this car are… unique. The front calipers are normal, from a Granada I believe. On the Tasmin its two-piston calipers and solid rotors up front. I think the bigger engined cars upgraded to vented rotors with the same caliper (with spacers in the caliper to accommodate the wider rotor).

The rears, on the other hand, are more unusual, having been taken straight from a 70s Jaguar XJ. They’re inboard, with the whole brake system in sitting next to the differential, instead of out near the wheels. Way overkill for this little car (so is the differential tbh).

This makes servicing the rear brakes a little less than ideal, as everything is tucked away in the middle of the car, surrounded by bits of suspension and tube frame chassis.

The first step to doing any work on the brakes was to get the car in the air. Unfortunately due to the placement of the frames I couldn’t use the Quickjacks to lift the car this time as I wouldn’t have the space to change the oil if I did (frame would be right under the sump). The TVR isn’t too hard to put on stands though, but the front is low enough that I cant get the jack under it without running it up on boards first.

Before working on the brakes I took the chance to change the oil. It didn’t look too bad on the dip stick, but it had to be at least two years old, and who knows how many KM since it was last changed. I drained it out, to find it was a dark grey/brown colour and smelt quite unpleasant. I guess it didn’t like sitting either.

A new Ryco Z71 filter and 4.7L of Penrites finest HPR30 finished off the job nicely.

I haven’t run the car much since, but the engine does seem to be a little quieter when cold, but now I know and trust what’s in it.

Moving right along, onto the brakes. I wanted to check the non-functioning hand brake first, as that’s the main issue that will stop the brakes passing a WOF inspection. The system isn’t too complicated; There are two little calipers attached to the main calipers in the rear, which are actuated by a cable, to clamp onto the brake rotor. These little calipers are meant to be self-adjusting, but they’re known to not self adjust very well and need to be set up right.

Obviously the cable had too much slack in it for a start, as the lever almost points at the sky when pulled, but the real issue is the adjustment of the pads, as there was little to no clamping happening.

To adjust the hand brake, first back the cable completely off using the 13mm nut (green arrow) on the end of the cable. There is another 13mm nut (orange arrow) on the other side of the lever, out of sight, which will need to be “tightened” to allow the slack to be taken out of the cable.

Next the split pin in the adjuster needs to be removed

And using a big screwdriver, turn the screw clockwise until you cannot spin the hub anymore. Now back it off until you can slip a split pin through again, and that’s that side done. Now adjust the other caliper the same way.

To finish the job you need to tighten the cable to remove slack. First back the hidden nut (orange arrow in above photo) off and using the nut you can see, wind in on until the slack is taken up, and then wind the hidden nut back towards the lever to lock the cable into place. With any luck, it should all be adjusted now, and ready to go. Three clicks of the lever is ideal.

Since I was under here, I took this as a good opportunity to flush the old brake fluid through and replace it with new, and bleed the braking system. Once again the old fluid is who knows how many years old, and was looking rather brown. Brake fluid should be replaced every two years as it absorbs moisture in the air, and becomes less effective (and can cause issues with blockage and rust if it’s really bad).

I used my new vacuum bleeder to suck the old fluid out of the master reservoir. I’ve seen better fluid. It should be a nice clear yellow. I topped up with fresh Dot 4 fluid.

What came out of the rear brakes was darker than that, so obviously its been a while since the rears had been flushed. Not really that surprised, since the bleeder on the rear is such a pain to get to. Its tucked away behind this tube. Very hard to see, and limited space to swing the spanner.

There is only one bleeder on the rear; on the passengers side. The calipers have a link pipe, so bleeding one bleeds both. I made sure to suck through a lot of fluid to flush both calipers.

With the rears flushed I moved onto the front. The front is comparatively a breeze to work on, even if someone had put a brake hard pipe right in the way of the bleeder. Nothing a gentle bend cant fix.

Strangely, the fluid that came out of the front calipers was much cleaner than the rear. I suspect someone had bled the fronts without bleeding the rear. Nice one.

The vacuum bleeder is good for sucking fluid through, but I have more faith in the old one-man bleeder for actually making sure no air is in the system

You may note that a couple of photos show no brake pads. This was the next job after flushing and bleeding the brakes. I removed the pads to check the pistons weren’t stuck and could be pushed back. Turns out the front pads are a set of near new Redstuff Ceramic pads. These are a good high performance street pad. A good upgrade.

Both front calipers responded well, with the pistons moving freely back, so that’s a relief.

The rears aren’t as much fun to work with. I found it easiest to work on my back with my feet out the back of the car. The pads are held in with two pins, which are secured with an R-clip each (like the fronts). I found on my car that one caliper had both pins inserted the same way, and one had the pins inserted from opposing sides, which meant that the location of the R-clip was different on each caliper

I used a small flat blade to pull the clips out, and then the pins just pushed out by hand. The pads took a little levering to get out but weren’t too hard. The pistons on both rear calipers moved freely also, so another win. I’m sure I have receipts for the brake calipers being replaced a few years ago, so might explain why they’re still in good shape. So hopefully that means the rotors just need a good hard pounding to get the rust and rubbish off them, and we might have some luck.

Unfortunately even with the hand brake adjusted as it is (three clicks maximum), it’s still not quite enough to hold the car on my driveway. It should be enough to pass a warrant, as my driveway is trial by fire and far too steep, but I’m hoping I can bed the pads in and get better performance once I drive the car a bit and the rust is knocked off.

I’m getting closer to having the car ready for its WOF inspection. Slowly but surely, we will get there.

In the meantime, I made the car look a million times better, with one easy step. Tyre shine. The old 10-15 year old rubber was looking somewhat dry.

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