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MG Midget and Sprite Technical - 76 BRAKE ISSUE(S)

First, Merry Christmas and Happy New Year to all.

Now that my 76 1500 midget is running great it would be nice if I could get it to STOP! About 6 months ago I rebuilt the master brake cylinder, the 2 front disc calipers, and the 2 rear wheel cylinders. This was the first thing I did to my project before anything else. All seemed to be OK. Brakes worked when I spun the tires and seemed good after I bled them. Now I cannot get a firm peddle and bleeding seems to do nothing. Fluid will not even come out of the rear brakes. The front ones will bleed, but no air comes out. When I push on the peddle hard brake fluid squirts up and hits the top of the plastic master cylinder cap. I "think" I might have put on the master cylinder rear brake rubber cup on backwards or something like that. I was going to remove the master cylinder and see what it looked like inside, but first I thought I would solicit advice from you experts before I went to all the trouble of removing the master cylinder. Thanks ......AL
AL MILLER

And a Merry Christmas and Happy New Year to you.

As for your problem, check to see if the master cylinder is returning back to normal after you let up on the pedal. You may not have enough play in the push rod to the pedal. You may also have a collapsed rubber line that goes between the main line on the frame and the rear axle. That's where I'd start before pulling the master. I'm sure others will soon have more suggestions.
Martin Washington

I had a situation where I had no air and still had a soft pedal and it turned out it was a stuck piston in one of the calipers. I don't think this is the case here.

There might be a problem with the master cylinder and perhaps the seal is in wrong. The lack of fluid at the rear leads me to think there is something wrong with either the master or there is a blockage somewhere and as has been said, possibly a rubber flex line has collapsed inside and not allowing the fluid to move in the line.

It might take some time to sort out but it will probably be something small and easily correctable.

Clive Reddin

I have found that the Master Cylinder is difficult to rebuild and have even gotten new ones for the Midget that were defective out of the box.

Rear brake cylinders tend to pit quickly at the lowest point unless the car is driven constantly. When you rebuilt these, if the bores were smooth, they might be OK. I would change the rear rubber hose first to see if you get fluid from the master to that point. The hose, unless it has been changed before, is due for replacement anyway, preferably with a braided piece.

If the car is stored or driven infrequently, the brakes really suffer.
Glenn Mallory

Thanks everyone for your input. I will get going on your suggestions this week ....AL
AL MILLER

You guys were right about the rear brake hose. I pulled it today and it was completely blocked. Don't know why because it was OK 7 months ago, but.....I will replace it and then bleed and see if that solves the problem before I pull the master. Thanks again .....AL
AL MILLER

Regardless of faults elsewhere, the master should not squirt fluid out the compensating port as you describe. Take it off!

FRM
FR Millmore

Well, FRM was correct. My new rear hose opened the rear brake hydraulic system, but fluid is still squirting from my rear master reservoir when I apply the pedal. Guess I knew that all along, but just "hoping" that it would fix it! So I puller the master and all looked OK? My cylinder does have a little wear in the form of a slight grove mid way in the cylinder, but it otherwise looks nice and shiny and smooth. Recall that I rebuilt it back in May of 09, but haven't used the brakes since. I noticed that the middle rubber cup (16)on the master shaft faced the opposite direction than the other 2 cups. I checked with my Hayes book and that seemed correct. Attached is a pic of the book pic and my shaft. The cups all look good. Any suggestions?? Thanks .....................AL


AL MILLER

This thread was discussed between 25/12/2009 and 05/01/2010

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