To: 80scool@yahoogroups.com From: "danamotors" Date: Mon, 26 Apr 2004 16:24:38 -0000 Subject: [80] Brake issues Reply-To: 80scool@yahoogroups.com Hello all you 80 experts. I'd like to ask a couple of questions about brakes, and also post my recent experiences on the subject. The truck is a 1991 FJ80 with 94 front calipers and disks. I installed a set of Axxis ceramic brake pads that are larger sized to fit the 100 series. They slipped right in with absolutely no modifications at all. I did NOT machine the rotors. They were pretty flat and no scoring at all. I installed the MAF set of braided brake lines. Two come in the kit, one each, front and rear, from frame to axle. I had a local racing shop fabricate a pair of braided lines for the calipers, as MAF or Slee doesn't sell them. So all 4 rubber brake hoses have been replaced with brand-new braided lines. Rear brakes are fully adjusted, quite tight. Handbrake comes on after 4-5 clicks. The brakes were very poor, the truck didn't want to stop quickly even with extreme pedal pressure, and the pedal felt extremely soft and mushy. this despite thorough bleeding. The 100 pads and braided lines went on simultaneously. Upon completion the brakes still felt pretty mushy. After a week or so of driving the front pads have seated and now the truck stops much better. These pads make a big difference. I was in the desert this last weekend and came down a very long steady descent. Normally I'd shift into a lower gear to hold the speed down, but I decided to test the claim these Axxis pads are fade-resistant. When I got to the bottom of the hill (about 4 miles), the brakes were still 100% effective. They were also quite HOT. I could smell them from inside the truck. The old pads would have been rendered quite ineffective at this temp. So, these pads do actually stand up to extremem heat and still perform normally. However, the pedal is still a bit mushy. Sitting still, I can apply pressure, and the pedal will still go down further than what I would consider normal, considering the braided lines. I would expect the pedal to be very firm once resistance is encountered. That's not what's happening. This is despite thorough bleeding, including the proportioning valve. The only thing left, from what I can see is the master cylinder. Would a M/C fail in such a way that it would feel mushy, but still apply fairly decent pressure? Is it a possibility that the proportioning valve could cause these symptoms? any comments/suggestions welcome.. thanks Dana To: 80scool@yahoogroups.com From: "michael_baltzly" Date: Tue, 27 Apr 2004 02:23:07 -0000 Subject: [80] Re: Brake issues Reply-To: 80scool@yahoogroups.com --- In 80scool@yahoogroups.com, "danamotors" wrote: > Would a M/C fail in such a way that it would feel mushy, but still > apply fairly decent pressure? If the master cylinder is bad it will typically allow the pedal to keep sinking lower if you hold your foot on the brake for a minute or so. If there is air in the system it will feel soft, but the pedal will only go down until the air is compressed and then no farther. Mike