also makes a hydraulic noise and the brakes dont work, when you push really hard they will work again
GMC Q&AAsk Your Question
1998 GMC Jimmy Question: What is wrong and what is the fix, sometimes when Im braking the pedal gets hard
Answer #1pushrod November 13, 2012, 21:04Master
Check vacuum at brake booster if ok have booster replaced.
Replygoodguy, November 13, 2012, 22:56Master
I agree with wetry
Replyziptie12, November 15, 2012, 09:12Master
I agree with goodguy.
Replybarry christianson, November 15, 2012, 15:06Rookie
If I pull the abs fuse the brakes work fine, would it still be the brake booster?
Replypushrod, November 15, 2012, 15:16Master
You didn't mention the ABS light was on! Have the system scanned, lots of sensors, the module, valves ect. it could be.
There will be codes if you put the fuse back and drive it then scan. Or leave the fuse out but you will no longer
have anti lock brakes. Most common problem is wheel speed sensor(s) or connections. But not the only one.
Answer #2Greg's Orange Auto (13388 Answers) , Orange, CA - (714) 361-9386globalhelper November 14, 2012, 06:10Master
sounds like power brake booster is bad
Replybarry christianson, November 14, 2012, 14:53Rookie
where is the brake booster located?
Replypushrod, November 14, 2012, 14:59Master
It is the big black round thing behind the master cylinder. Suggest towing to repair shop!
I agree with everybody.