Brake issue

[Dinkfore]

I need some brake help.I bought my kid an 85 mr2 and it had almost no brakes.I put on new brakes all around and bled the old fluid out because the car had been sitting for over a year.The problem is the pedal firmness is in direct proportion to the amount of pressure applied.If you push hard on the pedal the brakes lock up.If you push them slowly they don't grab till the very end and feel really soft.I'm thinking either master cylinder or booster but I thought 'd ask some advice first.
Any help would be great.

[BDSL]

Master Cylinder...

[mr2tim]

Well, congradualtions on buying your "kid" a mr2 they are a very safe car in accidents from the front and rear. (been there done that)

I too, suggest you investigate the pressure output of the mast cly. There are kits available that replace the entire plunger assembly so there is an alternate to replacing the whole assembly if you are so inclined.

You might check that mast cly bore for rust if it's steel, you can obtain a bore grinder to fix it? (1" bore hole)

There are aluminum replacements that don't degrade that were used in the later years.

The booster vacuum runs off that 5/8" rubber line that passes next to the water fill opening and terminates at the rear of the throttle body. Just for your reference.

Go with the mast cyl work 1st, that booster is a HUGE pain in the shorts what with standing on your head inside the footwell.

Make sure your "kid" at least watches your repair, there's no better way to bond with the kid's than car work. And, if your kid is a boy he should learn this stuff from you as soon as possible.

You sound like a good dad,

Tim
ToyZ RacZing
A Toyota Race Team since 1986

Originally Posted by Dinkfore

I need some brake help.I bought my kid an 85 mr2 and it had almost no brakes.I put on new brakes all around and bled the old fluid out because the car had been sitting for over a year.The problem is the pedal firmness is in direct proportion to the amount of pressure applied.If you push hard on the pedal the brakes lock up.If you push them slowly they don't grab till the very end and feel really soft.I'm thinking either master cylinder or booster but I thought 'd ask some advice first.
Any help would be great.

[Dinkfore]

Thanks for the replies!He's pretty excited about driving it but he doesn't have a lot of experience so until I get the brakes consistent he's got to wait.

[Dinkfore]

Thanks guys.Changed the master brake cylinder and they work perfect now.