Thomas A
Registered User
Wondering if I could get some thoughts on next steps to resolve my ongoing brake issue.
1997 Thunderbird 4.6L SC
4 Wheel Disc, No ABS
Symptom: Soft pedal, weak brakes
Replaced: Master Cylinder, all calipers, rotors, and pads
(verified bleeder valves are pointing up on calipers)
I bought this car having terrible brakes; Decided to go through and replace major components (upgraded to PBR on front) and issue has not changed. The MC was bench bleed, and I have run what seems like a gallon of new fluid through the system bleeding them. They have shown some improvement, but not much. I have inspected everything and see no leaks or fluid loss.
Last night after bleeding the front brakes yet again, the car for whatever reason wouldn't start. It cranked but wouldn't fire. I wiggled the connector to the CPS and it fired up. Backing out of the garage the brakes were awesome; grabbed very quick and hard. By the time I moved the car around and used the brakes a few more times, they were right back to their soft, awful status.
Wondering if this is a vacuum related issue? Perhaps the additional cranking of the engine produced enough vacuum and once it was up and running, it was gone again. The pedal isn't hard, so the booster seems to be working just fine. Also seems to hold vacuum very well (pull off vac hose hours after engine is off and still makes a large wooshing sound). My SC had a big cam (not enough vacuum) and the feel was completely different. It would go from good brakes to none with a hard pedal when the vacuum ran out. This is just consistently soft, poor performance, so not sure vacuum issue makes sense.
Any ideas what else to check. Why would they be so soft, then perfect for a couple of applications right after bleeding last night, and back to soft? Any insight would be appreciated.
1997 Thunderbird 4.6L SC
4 Wheel Disc, No ABS
Symptom: Soft pedal, weak brakes
Replaced: Master Cylinder, all calipers, rotors, and pads
(verified bleeder valves are pointing up on calipers)
I bought this car having terrible brakes; Decided to go through and replace major components (upgraded to PBR on front) and issue has not changed. The MC was bench bleed, and I have run what seems like a gallon of new fluid through the system bleeding them. They have shown some improvement, but not much. I have inspected everything and see no leaks or fluid loss.
Last night after bleeding the front brakes yet again, the car for whatever reason wouldn't start. It cranked but wouldn't fire. I wiggled the connector to the CPS and it fired up. Backing out of the garage the brakes were awesome; grabbed very quick and hard. By the time I moved the car around and used the brakes a few more times, they were right back to their soft, awful status.
Wondering if this is a vacuum related issue? Perhaps the additional cranking of the engine produced enough vacuum and once it was up and running, it was gone again. The pedal isn't hard, so the booster seems to be working just fine. Also seems to hold vacuum very well (pull off vac hose hours after engine is off and still makes a large wooshing sound). My SC had a big cam (not enough vacuum) and the feel was completely different. It would go from good brakes to none with a hard pedal when the vacuum ran out. This is just consistently soft, poor performance, so not sure vacuum issue makes sense.
Any ideas what else to check. Why would they be so soft, then perfect for a couple of applications right after bleeding last night, and back to soft? Any insight would be appreciated.