Bleeding front brakes

[650Hawk]

I blew a front brake line this week (luckily I had just left the house, and although I did end up running a stop sign, I missed the oncoming car!

). Anyway, I've gotten new front brake lines and will be installing this weekend, but had a question. Since I won't be touching the rears, I should be able to just bleed the fronts only, right? Anything unique or special I should know? I've bled plenty of brakes in my time, but do seem to remember reading here that the rears take a slightly different procedure. Any hints would be appreciated; thanks in advance.

 

[Nikal]

I blew a front brake line this week (luckily I had just left the house, and although I did end up running a stop sign, I missed the oncoming car!

). Anyway, I've gotten new front brake lines and will be installing this weekend, but had a question. Since I won't be touching the rears, I should be able to just bleed the fronts only, right? Anything unique or special I should know? I've bled plenty of brakes in my time, but do seem to remember reading here that the rears take a slightly different procedure. Any hints would be appreciated; thanks in advance.

Since you blew a line you have introduced air into the system. I would bleed all 4 wheels, starting with the rear passenger as that’s the farthest one away from the master. Then the rear driver, then the front passenger and last is the front driver. This is a good opportunity to flush out the old fluid and get fresh fluid through the brake system.

This can all be done the good old manual way of pumping, hold, bleed. But if you have a vacuum bleeder it makes it much easier and way quicker. I think you can buy a simple brake bleeder kit a Harbor Freight for $40. For some kits you will need a compressor or some form of air tank to pull a vacuum. Or you can find some that are like a pesticide bottle that you pump up. Look on Amazon I’m sure they have something for a decent price.

I have a real nice kit, that can also filling the master cylinder reservoir as I’m pulling fluid, so I don’t need to stop and keep checking it. If you run the master down you will introduce air and have to start over. But for a one or two time job the cheaper bleed kits do just fine, especially if you can get you a helper for 20 minutes to watch and fill the master as you’re pulling fluid.

Also plan on buying two large bottles of Dot 3 or Dot 4 brake fluid as you will use it.

 

[alrock]

With the H3 if you're bleeding brakes, specifically the rear, with the brake pedal (the old fashioned way) the ignition must be on or it won't work. Engine does not have to be on.

 

[650Hawk]

Since you blew a line you have introduced air into the system.

I'm not 100% sure that's the case. All 4 wheels' brake lines go all the way to the master cylinder; at no point are they common. So if I didn't allow the reservoir to get all the way down, the only line with air in it should be the one that I blew. I'll look closer tomorrow when I dig into it. I might start by trying to bleed just the fronts (I blew the right, but will be replacing them both). Worst case scenario, I have to start over and do all 4 corners.

With the H3 if you're bleeding brakes, specifically the rear, with the brake pedal (the old fashioned way) the ignition must be on or it won't work. Engine does not have to be on.

Thanks, I knew that there was something different about the H3 rears than most vehicles.

 

[EndeavoredH3]

Gravity bleeding has worked best for me, takes longer but you can walk away for 5-15 minutes to do other stuff.

 

[Jeepwalker]

Most likely after blowing a hose, you will have to activate the ABS bleed sequence with a scanner to bleed air out of it. If you don't have a scanner that can do an ABS brake bleed, ask around in advance and borrow a buddy's scan tool and plan on performing the ABS bleed once you've re-bled out the M/C. Snap-on scanners, and other scanners, which cover your year can do it. Sometimes i've had to do an ABS bleed sequence 2x. Plan on bleeding all 4 brakes. Good idea to exchange years-old brake fluid anyway.

Alternatively, if you can't find anyone who has a scanner that can do a brake bleed, ....if a guy can get some sort of firm pedal, then he could go on a gravel road and with 2 wheels on the gravel edge (of a county road), lock the brakes up hard (and long) so the abs comes on. Or large gravel parking lot. Then do the same for the other side. Then he should go home and re-bleed any air downstream of the ABS (all 4 wheels). Keep the M/C topped off in the process.

 

[650Hawk]

Well, it certainly wasn't anywhere near as involved as some of you have made it out to be, at least for my situation. Limped it home (had to make 3 add'l stop signs to get home, plus the driveway (E-Brake to stop before hitting the garage door!). Actually pumped the brakes a few times in the driveway trying to determine what happened, looking for leaks at the firewall (did not yet know that I blew a line), and by that time the entire inside of the right front wheelwell, suspension, shock, hub, inside of the wheel/tire, etc were covered with brake fluid as well as a 2' diameter puddle on the ground.

Got the new lines delivered, and started looking at the setup. So here's what I found: Each corner on the H3 has a dedicated brake line that runs all the way to the master cylinder; at no point do any of them share fittings/lines, etc. Which means that I was able to replace the front passenger line (the one that blew) and bleed it normally by itself. Took it for a drive...perfect; no air in any of the other lines! Went ahead and followed up by doing the driver side the same way; again no problem bleeding it by itself. No need for 4-wheel bleed, ABS bleed sequence, scanner, etc. I think that 2 things allowed this: One, the dedicated lines from each corner all the way back to the MC, and two, the brake reservoir never got quite low enough to introduce air into any of the other lines.

Whoohoo! Back on the road again!

 

[Jeepwalker]

Cool!

Just curious, is there no ABS in your system?

 

[650Hawk]

Of course there is. Do you know of an H3 without ABS?

Again, I think I got lucky in that the reservoir never got low enough to introduce air into any of the other lines. I've bled lines in other vehicles with ABS as well, and never had to do anything with the ABS/scanner.

 

[H3Hummer]

Bleed all 4,always, it's safer to push air out !
I do it old school, with engine runs, my wife pumps 4-5 times and i do open an close the bleeder and check or refill the fluid level after each break. Never get below minimum level! Works best for me, any time and any rig.

 

[650Hawk]

Bleed all 4,always, it's safer to push air out !
I do it old school, with engine runs, my wife pumps 4-5 times and i do open an close the bleeder and check or refill the fluid level after each break. Never get below minimum level! Works best for me, any time and any rig.

If there is no air in the other lines, there's nothing to push out. Now the argument can be made that the fluid should all be changed out every couple of years anyway, and I'm not disagreeing with that. However, I just thought that it was interesting that our H3s don't require a full 4 wheel bleed if only one line has blown. Open/pump/close/repeat is exactly what I did, but only on one line (actually followed up with the second line as well since I replaced both fronts).