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NO Brakes in 4LOW

4K views 40 replies 19 participants last post by  phil1330 
#1 ·
I dropped the jeep off at the shop to get gears installed front and rear the other day. The shop did the job but when i got in the jeep to test drive it the brakes were very weak.

I took the calipers off of the front and cleaned them with brake cleaner thinking the shop guys got there greasy *** hands all over the brake pads. And yes there was a little.

any ways the jeep stops ok on pavement in 2wd. It stops a little worse in 4 high, but it will not stop at all in 4 low. WTF!

Here's the set up. 88 wrangler w/95 booster and master cylinder. New brakes on all four corner.

What's the fix here guys?
 
#2 ·
Is the pedal firm? Could it need bleeding. How about your booster, everything hooked up? In 4low it always seems the brakes aren't as strong, when you say it won't stop are you saying you feel no brake action or they just seem really weak?
 
#3 ·
Nah when i say it will not stop in 4 low i mean i would be out of complete control of jeep on a down hill trail. That brake pedal is down to the metal. And i did bleed the brakes first b4 i cleaned the pads and rotors.(forgot to post that)

And yea the pedal feels ok but not as firm as it should i think.

booster is hooked up properly and vacuum line is secure with no leaks
 
#6 ·
I see no reason for the shop to touch anything to do with the brakes when changing gears.

I would have to think the two are unrelated.

In addition there is no relationship between your brakes and your transfer case.
Switching to 4low cannot affect your brakes. It may amplify an existing problem though.
 
#10 ·
They had to pull the axles to change the gears. To do that they had to remove the brakes.

Dwayne
 
#16 ·
If you're feeling good about no air in the lines, seems the next step would be master cylinder. Are you still running stock lines? I know you're turning some big meats, if you're running old lines might be good to change them, but unless their bulging, leaking or crimped they should not cause this.
 
#17 ·
I'm sure there is no air in the lines. I'm running stock hard lines but I'm running long stainless braided lines front and rear. No leaks no bulging. I haven't lost any fluid either.

I guess im gonna buy a master cylinder this week.
 
#18 ·
Here is my brutally honest assessment of this situation...

You had gears put in your jeep. The guy was probably lazy and didn't even unhook your calipers but instead just unhooked the brakes and figured he'd bleed them afterwards. Or he didn't even bleed them at all. Or he crimped a line or didn't get the connection between the rear brake line "right".

Either way your entire braking system has been compromised by something seemingly small but might be hard to diagnose.

You're on track to start something that you're probably not qualified to do (brake overhaul/master cylinder replacement) and you probably don't have the tools to do (have brake line flaring tool?).

My gut feeling is that you have air in your lines and need to go buy $15 (two quarts) of brake fluid and just cycle it through. If that doesn't solve your problem you need to mash on your brakes on some clean pavement for a couple minutes so you can find the leak. Act like Dr. House on this one...coincidences don't happen.
 
#20 ·
Act like Dr. House on this one...coincidences don't happen.
I'd have to agree. I also agree with others who have indicated that you take it back to the guy who did your gears. If everything was working before you took it in and now it's not, it's their problem, not yours.

Personally, I wouldn't touch it. As soon as you touch it, you bought it!
 
#19 ·
Sounds like the rear shoes need adjusting... in 4 low I don't care how good your front pads are they won't hold all 4 tires alone and the rear tires keep pushing unrestricted over powering the front brakes

The gear change just increased an existing problem you hadn't noticed... since I assume you went to lower gears now the extra leverage makes it really stand out
 
#32 ·
If you are running stock brakes otherwise I don't think you would benefit from that MC. It has a larger bore IIRC so unless you are running calipers that need more fluid volume you will just end up increasing your pedal effort. Also, I'm not sure if the e350 MC would seal to the booster (isn't there an o-ring seal on the 95 booster?). I'd just get a working replacement for the leaking part and you should be fine.
 
#40 ·
If everyone would just read his damn profile they would see he doesnt have stock axles, nor transfer case!!
Straight from his profile.
Year & Model
1988 YJ Wrangler
Engine
350
Transmission
turbo 350
Transfer Case
dana 300..chrome moly ft and rr Fred shafts
Front Axle
full width 10bolt w/30 spline chrome moly axles
and detroit locker
Rear Axle
full width gm 12 bolt w/detroit locker
Gear Ratio
5.38
Suspension
SOA, 4" rubicon, 1" shackles,
2"body
Tires
42 tsl

OP my buddy has pretty much the same setup as you (axle wise)and he just swapped in the E350 master cylinder and his brakes finally work properly. I also run an E350 with a dana30/ford 8.8 and it did wonders on my braking ablillities. Not sayin you have to go that route but it sure helped my buddies rig. I used a 1985 ford Van E350 master cylinder Part # M2008 and to fit the jeep hard lines to the new master cylinder I used 1/4x5/16 weatherhead # 7828 and 1/4x3/16 weatherhead # 7917 fittings.
It isnt a complete bolt in. You have to drill out the holes on the master cylinder to fit the smaller pattern of the yj booster and the ears of ther master cylinder need to be ground down a bit to fit on the booster other than that its a real easy swap.
Good Luck
 
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