brake problem

[2deuce]

My daughters m1009 has sat for over a year and now that she started driving it again a brake problem has developed. I have searched but didn't come up with a matching problem. Idling it can have a good pedal but moving the pedal can go soft and reach the floor in a stop. The soft pedal can revert to a full hard pedal only to lose it again a few seconds later. It can go hard too, when pulling into a parking space all of a sudden it stops short because the brakes came on hard without more pressure on the brake pedal. It did that once going around a corner at about 30mph, when the front wheels locked up. I'm planning on getting a new MC tomorrow. I can't think of anything else it might be. The truck steers normal, I think the PS pump works correctly. Thanks for any advice.

 

[Cucvnut]

Sounds like a bad MC

 

[mistaken1]

Or is it the power booster intermittently providing boost.

 

[Rustmaster]

Dude check the fluid in the power steering pump, mine did a similar thing. I guess it has something to do with the hydraboost.

 

[BIG_RED]

Could also be hydraboost related. Those units can do weird things when the seals go on them.

 

[2deuce]

Well, the PS fluid was low, but filling it didn't help. The main symptom is that if the brakes are applied very slowly the pedal will go almost to the floor before the brakes begin to hold. a fast stop the pedal will stay up, usually. I'm going to change the MC 1st, then look at the hydraboost if necessary. Thanks

 

[2deuce]

I changed out the MC and that cured it. I like the fact that these vehicles are relatively easy to work on. My ford pickup went out of warranty and so did the MC on it not long after, but it was so buried in there I had the dealer do it. That cost me almost $900, the MC itself was $700+.

 

[rnd-motorsports]

Glad to see you got it fixed!