Master Cylinder Cap

[jvandyke]

First let me say I consider this a temporary solution since brakes are important and a sealed master cylinder is important to keep moisture out but when in pinch.....the threads in my master cylinder cap fell apart, I grabbed the closest thing, a bottle of WeedBGone, big ugly yellow safety type cap. Screwed on fine seems tight, seems sealed. So if you need a cap, well chances are pretty good there's one within arm's reach that'll get ya by. Maybe they're all the same, coolant bottle? Anyway there ya go.

[DennisGardiner]

On your next trip down to the local wreckers.
Look for a late 70's to early 90's ATE master cylinder in just about any European car. Remove the plain black plastic cap and take it home.

Take your original Opel GT cap (with the metal hat & inner rubber boot) and disassemble the unit removing the broken plastic threaded insert.

You will notice that the cap with the threads you just pulled apart is identical to the one you received from the wrecker.

All you do next is clean, de-rust, paint & reassemble all three parts as original.
And Walla, You have a restored Opel GT cap.

Of course if you metal cap is dead, just use the wrecker cap as is.

[soybean]

Great tip Dennis. Thanks, from a lot of us I'm sure. Jarrell

[kwilford]

And if you look at many of those ATE MC's, particularly early BMW 3 Series, the MC cap comes with a float and a set of terminals that work very well as a brake fluid level monitor. They fit right on the Opel MC and provide a pretty handy warning when your booster fails and sucks all your brake fluid into the engine

[soybean]

All right Gentleman, now that we've got 2 real good tips? Who will make it three?
Jarrell

[yellaopelgt]

OK.. The metal on my cap is good but the threads are broken. So I went and got a rusty Opel cap with good threads and tried to pull it apart and cant seem to figure out how you can do this??? I'm afraid I'll end up breaking somthing if I pry too hard. Whats the secrect ???
Joe

[BQS4]

All right Gentleman, now that we've got 2 real good tips? Who will make it three?
Jarrell

Jarrell;
Here's another one for you. I bought a set of the BMW version 75 Opel calipers and they came with used brake pads in them. They are identical to the Opel 75 pads, but, one addition. There's a sensor wired to one pad in each caliper to be plugged into the BMW's system to indicate when the pads are worn to the point of needing to be changed. This could be simply rigged up for Opels.

[yellaopelgt]

Got the old cap out and realized just how easy this was....sorry...somtimes I tend to think about things waaay to hard...
Joe

[soybean]

I haven't tried prying my old cap apart yet, so that part I don't know about.
I tried the tip that Dennis gave using the brake master cyl cap off my 89 Saab Spg, and by golly it works. Not as pretty as the Opels but it works, plus it has the wire leads one could wire up to make a handy warning light.
Jarrell