Jeep Wrangler Forum banner

1 - 16 of 16 Posts

·
Registered
Joined
·
383 Posts
Discussion Starter #1
94, 2.5L, 5 speed. Recently replaced the front left, front right, and main back brake line. I bled the entire system today, thoroughly, twice. The brakes ARE slightly harder than they were...but only very, very slightly. Not even close to where it should be. (On the other hand, I bled them with the vehicle OFF-should I with it on, and thereby have the power assist?) Also, with all brake lines closed, if you pump the brakes they get harder....and then softer again. There are no detectable leaks anywhere. However, when you press the brakes, you can hear air somewhere...it sounds like from the master cylinder, but there is no liquid leaving anywhere. Is it inside the master cylinder? As we bled the brakes, the sound got quieter. I am so confused...please help? :(
 

·
Registered
Joined
·
383 Posts
Discussion Starter #2
Also, bear with me- To me, it seems thorough. First time I've bled brake lines. but there was no air coming out, and I've used every trick I can think of, or have heard of.
 

·
Registered
Joined
·
787 Posts
Did you bleed from the right rear, left rear, right front to left front? Did you have someone pump the pedal three times and hold it while you cracked the bleeder and tighten it? Did you run low on brake fluid at any point while bleeding it? If you did start over.
The bad news. If all checked out you maybe bypassing in the master cylinder.
 

·
Registered
Joined
·
383 Posts
Discussion Starter #4
Did you bleed from the right rear, left rear, right front to left front? Did you have someone pump the pedal three times and hold it while you cracked the bleeder and tighten it? Did you run low on brake fluid at any point while bleeding it? If you did start over.
The bad news. If all checked out you maybe bypassing in the master cylinder.
all check out. What do you mean bypassing in the master cylinder?
 

·
Registered
Joined
·
383 Posts
Discussion Starter #6
:banghead: I was trying to avoid that. Oh well..what happens happens. More I replace now, less I'll have to replace later.
 

·
Registered
Joined
·
29 Posts
It may also be the booster: Run the engine for 1 to 2 minutes and turn off. Press the brake pedal slowly three times. the pedal should be firmer with each depression. If it is it is holding pressure, if not ... Then start the engine and hold the brake down and turn it off. If there is no change in the pedal reserve travel after 30 seconds, the booster is air tight. My booster was corroded where it meets the master cylinder. The hardest part of the job was the clip holding the booster shaft to the brake pedal. I had to buy a new one from the stealer ( about $3.25). It cost him half that to mail it to me.
 

·
Hacks off Parts while Lit
Joined
·
2,290 Posts
if you ran the MC low, you might need to bleed it first, then bleed it at the wheels.

i bleed it at the wheels with the engine running so you can have the power brakes.
 

·
Registered
Joined
·
383 Posts
Discussion Starter #9
I'm doing the booster tests now, will post the results when I'm done. And what happens if I DON'T bench bleed the master? It seems like a major pain, considering I'd probably have to cut the old ones and flare new lines for it in order to get the old one off. Nuts are too rusted, need 6 point socket to do it. And my booster is corroded near the master..I'm just hoping it still holds pressure.
 

·
Registered
Joined
·
383 Posts
Discussion Starter #10
In my highly untrained opinion, the brakes DID get harder after leaving the jeep on for a few minutes, turning off, and pumping brakes, but only for the first three times, after that it stays at the same resistance, or starts to lessen. I wasn't sure exactly what you mean by the second part... but I turned on the jeep, pressed the break, turned it off, and pumped them, at which point they got harder. Would air in the master cylinder (because it did run out completely when the line broke originally) keep it from being as hard as it should be?
 

·
Hacks off Parts while Lit
Joined
·
2,290 Posts
i've bled the MC on the vehicle before. they have some plastic insert things that thread into where the brake lines are, and they have a plastic tube coming off of them. you put the end of the hose back in the reservoir, then press the brake to floor steadily a few times.

just to clarify the bleeding wheels portion, the way i do it is with the engine running, have assistant pump the brakes rapidly and then hold it. open the bleeder, close the bleeder, have assistant repeat. start at right rear, then left rear, then right front, then left front.

if the MC went dry, and the pedal still feels spongy, my money is on air at the MC.

get some PB blaster, wrap a string around the threads where the brake lines go in and soak it. (soak the string, wrap it around the threads. it might still brake anyway though....at this point though, id say you're committed. also, get some flare nut wrenches, they'll help keep the nut from stripping......
 

·
Registered
Joined
·
383 Posts
Discussion Starter #12
i've bled the MC on the vehicle before. they have some plastic insert things that thread into where the brake lines are, and they have a plastic tube coming off of them. you put the end of the hose back in the reservoir, then press the brake to floor steadily a few times.

just to clarify the bleeding wheels portion, the way i do it is with the engine running, have assistant pump the brakes rapidly and then hold it. open the bleeder, close the bleeder, have assistant repeat. start at right rear, then left rear, then right front, then left front.

if the MC went dry, and the pedal still feels spongy, my money is on air at the MC.

get some PB blaster, wrap a string around the threads where the brake lines go in and soak it. (soak the string, wrap it around the threads. it might still brake anyway though....at this point though, id say you're committed. also, get some flare nut wrenches, they'll help keep the nut from stripping......
Got some PB blaster, the string idea is nice. I have flare nut wrenches...but they stripped the old nuts on the lines I replaced in certain cases. I'll look into getting those plastic inserts. And yeah, I'll try bleeding the lines again as well. However, I have a question- and a rather silly one- On the back wheels is the bleeder simply the line that goes into it, and on the front brakes is it simply the soft brake hose where it attaches to the caliper?
 

·
Hacks off Parts while Lit
Joined
·
2,290 Posts
noooooooo

there is a bleeder valve on them. go in behind the wheel, and it looks almost like a grease zirc fitting. you loosen it to "open" the bleeder, then tighten it back up (but not stupid tight) before they release the pedal. on drun brakes, its located on the back of the wheel cylinder (will be at 12 o' clock on the backing plate). on discs, its located on the caliper

the plastic things im talking about for the MC i think are available at the HELP section at ghettozone/oreilly/napa
 

·
Registered
Joined
·
29 Posts
It sounds like your power booster is fine. you may not have followed the procedure exactly from the manual, but you still proved that it is holding pressure. Honestly, it sounds as simple as air in the lines i.e. cheep to fix.;)
 

·
Registered
Joined
·
787 Posts
You got some good info while I was gone. Nothing more to add except bleed that system again. This time using the bleeder Screws not the lines.:doh: Sounds like you are going to be a professional brake bleeder before your done. Hey good luck and keep us updated. Any other questions just ask.
 

·
Registered
Joined
·
383 Posts
Discussion Starter #16
After numerous silly mistakes, lots of lost brake fluid, and so on- It's done. The booster keeps pressure, the MC is fine...And Finally, the jeep itself is done. Except for the left running light, but that won't exactly be difficult. Thank you, everyone, for all of your input for an inexperienced 17 year old. Still, it's a good feeling to finish this thing after a year and a half of trial and error. Now, to learn to drive stick...also with trial and error >.>
 
1 - 16 of 16 Posts
Top