Re: Strange Problem With 1995 Wrangler

I would guess you have power brake booster issues or MC issues. The booster is the unit between the master and the firewall.

I also have seen rebuilt masters go 'hard' too. An internal seal or something went strange. The one I saw recently was standard brakes, so there was no power or vacuum issues, others I have seen in the past had a vacuum issue of some sorts that affected the idle if you pumped on the 'hard' pedal.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Paul wrote:

> Attention all you amateur and pro jeep mechanics out there...I have a > problem for ya > > I have a 1995 Jeep Wrangler, 5 speed, 4.0L engine. > The jeep is totally stock with P21575R15 tires (Goodyear Wrangler > Radials) > The jeep developed a problem last summer which has appeared again this > summer. After work, when the temperature is 88 or better, I jump in > the jeep to start the trek home. After I start up the jeep the brake > pedal feels hard to push. I still have very good brakes and it stops > ok, it's just that the pedal feels much stiffer. When this happens, on > the way home I have very little power going up hills. I usually have > to downshift to 3rd to make hills that I could normally make in 4th > gear. In the morning on my trip into work the jeep seems to run fine. > When the temperature is below 80 the Jeep seems to run fine. Before > you answer..here are some of the things I have already done: > > new spark plugs, distributor cap and rotor > > new ignition wires > > new oxygen sensor > > Jeep dealer put the scan tool on the computer and said I needed a new > crankshaft position sensor which he replaced. He also put fuel > injector cleaner in fuel rail and some other cleaner in gas tank. > He also set the timing to chrysler specs using the scan tool. > > Mechanic sprayed Gumout carb cleaner all over the vaccuum lines to see > if any were leaking. Found no leaks. Sprayed around the power brake > unit..no leaks. > > I had the brakes bled twice (I thought trapped air was expanding and > causing the brakes to drag) > > I adjusted the rear brakes with brake calipers and they are not > dragging. The parking brake appears to work ok. > > Both rear wheel cylinders new last year > > Rebuilt master brake cylinder put on last year.. > > New Clutch master/slave linkage installed > New clutch installed, but this was just done a month ago, long after > the problem had been noticed. Same for the clutch linkage. > > The fuel filter is less than a year old and the air cleaner is new. > > I'm out of ideas and I'm thinking of trading my beloved YJ in for a > (excuse the expression) rice box. > > My theories, none of which have been tested........... > > 1. A front brake caliper piston is sticking and causing a front brake > to drag. I smell no brake smell and the vehicle stops arrow straight. > Would a sticking piston cause a hard brake pedal? I dont think so. > Loss of manifold vaccuum causes the hard pedal. > > 2. The power brake booster is leaking internally when the temperature > gets really hot. I can jump into my jeep after work and press the > brake pedal in 2 or 3 times before I run out of stored vaccuum. Thus > the booster has stored this vaccuum for 9 hours...could the brake > power booster still be bad? > > What do you think??? Got any ideas?? > > Thanks in advance > > Paul
Reply to
Mike Romain
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My opinion....Needs a new "in tank" fuel pump. Now as for the brake issue, I can only guess is related to fuel pump, you have to put your foot in it more which causes less vacuum at the throttle body to be generated which depletes the vacuum boosters volumn of vacuum. That sounds kind of funky, but it think I said it as right as possible.

Greg

88 YJ Master Mechanic
Reply to
gbray

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