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1994 Jeep Wrangler brakes fail to hold in reverse

My 94 Wrangler brakes fail to hold in reverse when climbing a steep grade. This is especially dangerous when 4-wheeling and climbing a slope which increases causing down-shifting. The only way I can prevent rolling backwards uncontrollably is to feather the clutch in a forward gear… WHY?

Because your brakes are failing to hold. Get it to a qualified mechanic ASAP before they fail to function going forward.

Thanks for that sage adivce…

The front brakes have greater stopping and holding power than the rear brakes however when stopping or rolling backwards down a dirt incline the front tires tend to slide because of poor traction and it takes a lot of pedal effort to make the rear brakes do all the stopping.

No, actually what happens is the wheels turn and any amount of
pressure on the peddle does not hold the weight of the jeep. I know
that the “cam” action of the drum brakes enhances the breaking
ability in forward motion and have to wonder if this action is
“reversed” when attempting to stop rolling down-hill in reverse on
a steep slope. This could be a life threatening problem when
4-wheeling - which is what a jeep is for. I would like to hear an
engineer type explain what this could be and how to correct it.

Jim.

You don’t need an engineer , you need a brake shop . A break shop won’t help.

4 Likes

You are most welcome. Never had that problem with my all drum CJ5.

I also have a CJ5, a much better hill climber than a 4 liter Wrangler. Whether in my Jeep, dune buggy or truck there is too much front brake bias for this situation and when climbing hills and running out of traction there is always difficulty when backing down the hill.

Try hill climbing on a dirt bike, you can choose rear brake over front but when faced with backing down a hill you will wish you were in the jeep.

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Somehow I’m not interested in a dirt bike and haven’t been since I
was 75. The Jeep is the best option especially if carrying
equipment.

Thanks

… nor will a shop that specializes in “peddles”.
:thinking:

I strongly recommend that this vehicle be taken to a shop that fixes brakes, and that is familiar with brake pedals.
:wink:

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Front discs and rear drums? If so, are the rears properly adjusted? Of course, this would not account for the brakes failing to be able to lock the wheels.

One other possibility, could be the proportioning valve. Drum brakes are fully cable of locking up in reverse. Ever see a factory Cadillac Limo do a J turn?

No. Where do you live, Hollywood? For stunt cars a control valve installed can select front or rear brakes to perform certain stunts.

As far as locking the rear brakes in reverse, take and old vehicle like this at 20 MPH in reverse and try to lock the brakes. The front will lock easily, the rear, nearly impossible.

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It used to be (1960’s) that on rear drum brake vehicles the parking brakes didn’t hold as well to prevent moving backwards as frontward, so maybe there’s something to the OP’s theory that this has to do w/the vehicle having rear drums, and the way the braking forces are multiplied; i.e. maybe they aren’t multiplied as much in the reverse direction, very possible. When facing uphill the rear wheels have more weight over them than the fronts and are therefore more important for holding the vehicle from moving backward w/the brakes applied. On the other hand both my 90’s Corolla and 70’s Ford 4wd truck have rear drums and I’ve never noticed them to be weak at holding on a steep hill. The advice above to get the brake parts inspected is probably the best bet.

Thanks for the spelling corrections. I have taken it to the shops
you recommend and that has not produced good results. They have said
all is well. So even though you know spelling I find your obvious
suggestion of taking it to a shop condescending and not much actual
help, unless I am going to be in a spelling bee.

I am really more interested in stopping the vehicle than spelling

lessons - they have not worked for 77 years of my life so I have no
hope for further lessons.

I did get one suggestion from this site that may prove helpful - the

“proportioning valve”. That seems worth looking into.

Also, if you are the wordsmith responsible for constructing the

words you mention please explain just how you decided on the actual
spelling of such words. I would also like to know who decided on
such words as those for the numbers “1” and "2’. Phonetically they
should spelled “won” and “too” … so why is the "w’ sound for “1”
found in “twoooo”?(2).

And just for fun please spell the word for those lights that are

neither incandescent nor LEDs. You know the ones with the long
tubes. WITHOUT using spell check.

Lighten up everyone.

It could be the proportioning valve, the shoes are not adjusted properly, or the rear drums are worn too far and pistons cannot put enough pressure to create enough resistance.

The factory Jeep was not built specifically for “Rock Climbing”. It was made for transportation on the roads and to go off road. “Off Road” does not mean climbing boulders the size of a small house.
There has to be a compromise in engineering to build a vehicle to do both.
Think of it this way, a guy builds a monster truck, and hauls it to the show on a trailer…because it was built for one purpose.

Why not check out a shop that specializes in Rock Climbing trucks and see what others have done that have had this problem.

Yosemite

2 Likes

I don’t remember if I replied to your message but that is the most
helpful suggestion I have seen yet. I will have the
professionalizing valve checked, probably by dealer. I considered
that a while back but "Brake Master’s " mechanic said it was OK,
however I don’t believe he was able to Trail test it on a steep
slope. Thank you.

Thanks for your incite. The professionalizing valve is probably the
most likely culprit. I will have it checked - Thank you.

Well, my brother had a Wrangler of this vintage and it went almost anywhere. Mostly driver skills, it could tackle trails mostly reserved for the bigger rigs or specialized crawlers. One of my fondest (terrified) memories was a wicked steep incline w mountain face on one side and couple thousand foot dropoff 3ft past the passenger door. And it stalled, flooded and wouldn’t restart. Recurring issue with carb setup. The electric pump didn’t help with flooding either. So we had to back down to the prior switchback without power steering or power brakes. Applying brakes to stop every 5-10ft and can feel front get light every time it came to stop. Unconciously leaning forward in seat, realized my face is close to dash. Only felt like it would endo like that once before in pot feature in Utah where you could see at least one rig tumble backwards if you stuck around to watch. Anyway, original equipment style brakes could hold it no problem in attitudes like that. Something not right with your setup.

Btw- tore out that carb, coil and distributor setup and replaced it with ECM, TBI and HEI ignition. Never stalled on inclines at altitude again…

Good story with happy ending. My 94 YJ has fuel injection, stock,
even though it is a minimal type it overcomes the steep
incline/carburetor problem. I have had to replace the stock plastic
fuel lines due to a “flooding” situation - raw gas flooding the
engine compartment. Fortunately that happened near an Ace Hardware
where I could buy a rubber hose to bridge the gap. I later replaced
that with high pressure woven fuel lines just to be safe. Also This
model Jeep has a built - in problem with failing parking brake.
There was a recall so dealer will replace the assembly no charge,
but the design is the same so it continues to happen - but the
dealer just does a "recall re-do"each time . Especially scary at
the boat ramp when you hear the darn thing release and start moving
backward.

Thanks for the reply, someone suggested the proportionalizer valve

may be the cause of my problem - I’ll try that next.