Sunday 6 January 2013

Failing Master Cylinder....and Rust

Well, with getting everything ready for the MOT I came across one real problem with VIN 10719. The brakes had been playing up since I got the car from Southampton. After getting the car back home I'd checked the master cylinder and fluid reservoir and all seemed fine. The level was fine back then, but the brakes still seemed spongy, a problem which only seemed to get worse as time went on. Then a dreaded patch of clear oil appeared on the garage floor, right below the MC area of the car.


Sure enough the MC had been leaking oil out of the back, via the rear seals, down the front of the vacuum assist/servo unit and, worst of all, onto the frame. The DOT 4 fluid is very corrosive and had eaten away at the epoxy on both the frame and the tank cover.


Now, when had this all started. Some of the areas indeed look like they are pretty fresh. The epoxy has been damaged, but the steal below only had surface rust. But, further down the frame and on the tank cover the layer of rust was more pronounced, pointing to an older problem. Talking to the previous owner he assured me that "there had never been a leak", but the evidence does point to something that's been going on for some time. But, whatever the case this needs sorting.


Pulling the MC out revealed the problem with the rear seal. The whole area was dripping with fluid. The seal should stop any fluid finding its way back here, so that must be the point of failure. The question is what to do? The MC is original, and some searching on the net and questions on the forums revealed that to try and recondition the MC would be a false economy. The bore inside the MC was probably badly corroded and any reconditioning would be more expensive than a replacement.

So, biting the bullet, I purchased a MC through the DeLorean Eurotec club shop, which thanks to some excellent service turned up in a couple of days, and this over the New Year weekend as well!

With the MOT booked for the 3rd of January I needed to work fast. I pulled the old MC and servo unit out of the car and cleaned up and repainted the servo unit to look as good as new. The old reservoir is a part in very short supply, and was in great order, so that was transferred onto the new unit. Its held on with a couple of pins, so easy enough to do. 
All the new parts went into the car pretty easily, and the brakes were bled using an easy bleed system to pressurise the MC and fluid tanks. I've never done anything like this before, but it all seemed to go very well, and the brakes are transformed. 
The rust needs looking at, but I've already cleaned the black "tar" protection off the tank cover and affected frame area. Not a pleasant job! My car seems to have had this "protective" covering applied at some point. The previous owner had told me before purchase that it was a special "rhino" paint they use on flat bed trucks over there, but that's nonsense! This stuff is like a tar coating which can be scrapped off with a blunt tool. You'd never want it on the bed of a truck, it would get everywhere! I'll need to get it off all the frame, and that's going to be one hell of a job. But for now the brakes work, which is the main thing.

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