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I had removed the clutch slave to get at the oil pump to replace leaking pressure release valve so I decided to clean clutch cylinder and replace seals. The bore was a little rusted at the bottom edge where the piston seal doesn't reach and the bleed nipple was clogged with gunk so it wouldn't drain under gravity. Master clutch had rubber particles in fluid but other wise OK so replaced seals and decided to do brakes as well. Rear cylinder where a little rusted but I had new ones to replace. So far so good.

Pulling the brake master cylinder and pistons showed a clean bore so I figured I was home free. When I went to remove the pressure differential piston fron the front it was frozen. Quite rusty in there. Can't even move it with two screwdrivers pushing/pulling the switch ledge. (making up words here). I'm now soaking it with penetrating oil to see if that will release it.

Has anyone else had problem removing this piston and if so what was your experience with it?

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

OK, I soaked the pressure differential cylinder with penetrating oil overnight and with some coaxing with screwdriver through the switch hole the piston came out. Just a little rust but mostly just crud. I flushed out with CLR (stands for calcium, lime and rust desolver, not sure of it's availability outside of Canada). CLR is milder than say POR-15 Metalready and doesn't leave a coating like it. Everything looks good. No having to buy new master cylinder. On to the brake booster.

TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

Well done FI, I think you were expecting it to be more difficult.

We have CLR here. A lot of water in Oz is very hard, & its great for
getting the scale off things.
I did not realise it had so many other uses. I'll look at with more
interrest from now on.

Hasbeen

Is the pressure differential device REALLY necessary on a TR7 ? What happens if it's just deleted - ie by-passed ? Lots of Minis have the wretched thing removed in UK, and the brakes are all the better for it!