Disc Front & Drum Rear...........? This is a customers vehicle. The brake pedal is hard but very little stopping power. Acts like a bad booster or vacuum leak.
Here's what's been done so far, some by the customer and some by myself. Tested for good vacuum and tested for vacuum leaks including smoke testing intake, all is good. Two new boosters installed. Master cylinder replaced. Proportioning valve replaced w/new Mopar unit. All lines flushed, new fluid. Front calipers, pads and hoses replaced w/new. Rear shoes replaced and rotors and drums machined front and rear And of course muliple bleedings..
Vehicle still has exact same synptom. It almost takes both feet to stop it. I have a 90 YJ with the same system and I can lock em up with my big toe. But what the heck is left?? Seems like we've tried everything. BTW I have about 25 yrs as a Master Tech and I'm the Shop Foreman at the Jeep Dealership, so I'm not a greenhorn. But that doesnt mean I havent missed something.
Any suggestions would be apreciated...
You're right Kirk, I have'nt paid much attention to the pedal. Now that i think about it when I ren "hard pedal" in IDENTIFIX I got a bunch of hits for the booster and one confirmed fix for brake pedal, but there were no details about what they found wrong with it. I'll be crawling under the dash first thing in the morning. Thanks for the input!
Rick and Mike, Thanks for responding. I've already explored the pushrod travel having seen that before myself. No Luck. I adjusted it to spec and then loosened the master 1/8 inch at a time all the way to over 3/4 inch with the same results each test drive. Freeplay is'nt the issue. But you do have me thinking about pad composition. The customer had Wagner quiet stops on it and I replaced them with Raybestos PGD's. Which I've used a thousand times but you correctly pointed out that the original pads were organic. Something to think seriously about. I'll be looking into that seriously in the morning. Maybe even bumming a test set from the parts dept. (My parts mgr hates me for that! lol)
Thanks so much to you guys for responding. I really apreciate it.
I've had alot of cars fight me over the years but I've never let one beat me, and this one will not change that!
Thanks for the tips guys and keep em coming!
I promise I'll post the fix (and give cudos) when I (we) figure it out.
Also Rick...
I'm in the Denver zone. Dave Mowry is my DR and Barry Hollenbeak is our tech instructor. Barry is my buddy and I'm sure he'd give me Steve's phone or e-mail. Thank's for the idea!! I'd been hesitant to call STAR on this old of a vehicle. Did'nt think I'd get much help. But some of those Rep's and instructors are truly old school like us. Maybe I'll make some phone calls in the morning.
Thanks again!
Dave L.
Here's what's been done so far, some by the customer and some by myself. Tested for good vacuum and tested for vacuum leaks including smoke testing intake, all is good. Two new boosters installed. Master cylinder replaced. Proportioning valve replaced w/new Mopar unit. All lines flushed, new fluid. Front calipers, pads and hoses replaced w/new. Rear shoes replaced and rotors and drums machined front and rear And of course muliple bleedings..
Vehicle still has exact same synptom. It almost takes both feet to stop it. I have a 90 YJ with the same system and I can lock em up with my big toe. But what the heck is left?? Seems like we've tried everything. BTW I have about 25 yrs as a Master Tech and I'm the Shop Foreman at the Jeep Dealership, so I'm not a greenhorn. But that doesnt mean I havent missed something.
Any suggestions would be apreciated...
You're right Kirk, I have'nt paid much attention to the pedal. Now that i think about it when I ren "hard pedal" in IDENTIFIX I got a bunch of hits for the booster and one confirmed fix for brake pedal, but there were no details about what they found wrong with it. I'll be crawling under the dash first thing in the morning. Thanks for the input!
Rick and Mike, Thanks for responding. I've already explored the pushrod travel having seen that before myself. No Luck. I adjusted it to spec and then loosened the master 1/8 inch at a time all the way to over 3/4 inch with the same results each test drive. Freeplay is'nt the issue. But you do have me thinking about pad composition. The customer had Wagner quiet stops on it and I replaced them with Raybestos PGD's. Which I've used a thousand times but you correctly pointed out that the original pads were organic. Something to think seriously about. I'll be looking into that seriously in the morning. Maybe even bumming a test set from the parts dept. (My parts mgr hates me for that! lol)
Thanks so much to you guys for responding. I really apreciate it.
I've had alot of cars fight me over the years but I've never let one beat me, and this one will not change that!
Thanks for the tips guys and keep em coming!
I promise I'll post the fix (and give cudos) when I (we) figure it out.
Also Rick...
I'm in the Denver zone. Dave Mowry is my DR and Barry Hollenbeak is our tech instructor. Barry is my buddy and I'm sure he'd give me Steve's phone or e-mail. Thank's for the idea!! I'd been hesitant to call STAR on this old of a vehicle. Did'nt think I'd get much help. But some of those Rep's and instructors are truly old school like us. Maybe I'll make some phone calls in the morning.
Thanks again!
Dave L.