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Brake bleeding after caliper change
http://www.lostjeeps.com/forum/phpBB3/viewtopic.php?f=5&t=81852		 Page 1 of 1
Author:  BodhiBenz1987 [ Thu Apr 16, 2015 9:41 am ]
Post subject:  Brake bleeding after caliper change
I hope I've not missed this already being addressed, but I did a search and can't find an answer, which I need rather quick since the Jeep is at the dealer and I need to let them know.
I took it in for a timing belt change. Long story short, I happened to do a rear pad/rotor change the day before and found it dragging on the drive to the dealer for the belt change. So they checked it out for me and said I need calipers. They said they'd do it for $290, but I could drive it home if I wanted to do it myself. Since I can get calipers at NAPA for $100 total, I'd rather do that, but here's my question: Can I bleed it? I've seen some people say you need to bleed the ABS with a scan tool. Is that the case here? I have a Motive power bleeder that works great on my 87 Mercedes so I can do a normal bleed with that. But if I have to take it back to the dealer and pay them to do that ABS bleed, I might as well have them do the whole job in the first place while it's there.
Not a good feeling, as I sort of put in the effort on the brakes for nothing now ... :?
Author:  dirtmover [ Thu Apr 16, 2015 11:05 am ]
Post subject:  Re: Brake bleeding after caliper change
The fail safe state of the brakes is that, with effort, they will work without assistance and with no power to the ABS. As long as you don't get air into the ABS hydraulic unit you should be fine. If by chance you do get air in there you're towing it to the dealer or a shop that has the required third party tool :cry:.

If you wish to do a complete flush you need to be able to actuate the ABS solenoids.
Author:  thermorex [ Thu Apr 16, 2015 11:08 am ]
Post subject:  Re: Brake bleeding after caliper change
I bled my 2005 brakes without any special tool. Just connect a 1/4 inch hose to the caliper all way through a bottle/catch can and do few pedals and that's it...

But I know what you're talking about. I think your concern is more related to replacing brake pads than bleeding the system. Some cars sense the difference in pressure when you remove the pads from the caliper and it tries to adjust it. For those cars disconnecting the battery usually works, if you don't want to pay for an expensive obd tool that can put the brakes in service mode.

Also remember this is a jeep not a Mercedes :) . It's reasonable simple.
Author:  thermorex [ Thu Apr 16, 2015 11:27 am ]
Post subject:  Re: Brake bleeding after caliper change
dirtmover wrote:
The fail safe state of the brakes is that, with effort, they will work without assistance and with no power to the ABS. As long as you don't get air into the ABS hydraulic unit you should be fine. If by chance you do get air in there you're towing it to the dealer or a shop that has the required third party tool :cry:.

If you wish to do a complete flush you need to be able to actuate the ABS solenoids.


Do you think this is needed? I know for sure you can do a flush w/o actuate solenoids, I am asking from curiosity as I have never opened the abs module nor I have seen its schematics and I wonder if all the abs components get flushed without actuating the solenoids. The reason I don't think this is needed: the valves would allow the brake fluid to go through straight to caliper. When engine is stopped the valves must be opened and the brakes work as w/o abs. The pump in abs may be partially bypassed if not in use, based on how it's made, and this is why I think it may be required to have the solenoids energized at least a bit to circulate the flow through the pump, hence the question to your post.
Author:  65Corvair [ Thu Apr 16, 2015 1:18 pm ]
Post subject:  Re: Brake bleeding after caliper change
Bleed the brakes with your Motive Bleeder as normal. If you do get air into the brake system, then you need to take it is for the ABS system bleed. Motive power bleeders are nice, I really like mine.
Author:  tjkj2002 [ Thu Apr 16, 2015 3:26 pm ]
Post subject:  Re: Brake bleeding after caliper change
thermorex wrote:
dirtmover wrote:
The fail safe state of the brakes is that, with effort, they will work without assistance and with no power to the ABS. As long as you don't get air into the ABS hydraulic unit you should be fine. If by chance you do get air in there you're towing it to the dealer or a shop that has the required third party tool :cry:.

If you wish to do a complete flush you need to be able to actuate the ABS solenoids.


Do you think this is needed? I know for sure you can do a flush w/o actuate solenoids, I am asking from curiosity as I have never opened the abs module nor I have seen its schematics and I wonder if all the abs components get flushed without actuating the solenoids. The reason I don't think this is needed: the valves would allow the brake fluid to go through straight to caliper. When engine is stopped the valves must be opened and the brakes work as w/o abs. The pump in abs may be partially bypassed if not in use, based on how it's made, and this is why I think it may be required to have the solenoids energized at least a bit to circulate the flow through the pump, hence the question to your post.
To do a complete flush you need a brake pedal depressor holding the brake pedal halfway down and if you have ABS yes you will need to actuate the ABS module.
Author:  thermorex [ Thu Apr 16, 2015 3:57 pm ]
Post subject:  Brake bleeding after caliper change
tjkj2002 wrote:
thermorex wrote:
dirtmover wrote:
The fail safe state of the brakes is that, with effort, they will work without assistance and with no power to the ABS. As long as you don't get air into the ABS hydraulic unit you should be fine. If by chance you do get air in there you're towing it to the dealer or a shop that has the required third party tool :cry:.

If you wish to do a complete flush you need to be able to actuate the ABS solenoids.


Do you think this is needed? I know for sure you can do a flush w/o actuate solenoids, I am asking from curiosity as I have never opened the abs module nor I have seen its schematics and I wonder if all the abs components get flushed without actuating the solenoids. The reason I don't think this is needed: the valves would allow the brake fluid to go through straight to caliper. When engine is stopped the valves must be opened and the brakes work as w/o abs. The pump in abs may be partially bypassed if not in use, based on how it's made, and this is why I think it may be required to have the solenoids energized at least a bit to circulate the flow through the pump, hence the question to your post.
To do a complete flush you need a brake pedal depressor holding the brake pedal halfway down and if you have ABS yes you will need to actuate the ABS module.


Tj, what happens if you just flush the brakes as you wouldn't have abs module? Is it possible that not all fluid gets flushed from the abs module? I just want to know for my curiosity since when I bled mine, I just opened the caliper bleeder through a hose and catch can and kept pressing the pedal while making sure the reservoir on the master cylinder had enough fluid. I did each line, one by one.
Author:  tjkj2002 [ Thu Apr 16, 2015 4:28 pm ]
Post subject:  Re: Brake bleeding after caliper change
thermorex wrote:
Tj, what happens if you just flush the brakes as you wouldn't have abs module? Is it possible that not all fluid gets flushed from the abs module? I just want to know for my curiosity since when I bled mine, I just opened the caliper bleeder through a hose and catch can and kept pressing the pedal while making sure the reservoir on the master cylinder had enough fluid. I did each line, one by one.
You just don't flush out the old fluid inside the ABS module.When not activated the ABS module is totally blocked off from the hydraulic system so it's like it's not even there.

Now if you have a '06+ KJ the above is false since those have ESP and the ABS functions a lot more then you think so that little fluid inside that module will get mixed with the new so just do a 2nd flush a few weeks after the 1st for '06+ KJ's for a complete flush without needing to activate the ABS via scanner.
Author:  thermorex [ Thu Apr 16, 2015 4:56 pm ]
Post subject:  Re: Brake bleeding after caliper change
tjkj2002 wrote:
thermorex wrote:
Tj, what happens if you just flush the brakes as you wouldn't have abs module? Is it possible that not all fluid gets flushed from the abs module? I just want to know for my curiosity since when I bled mine, I just opened the caliper bleeder through a hose and catch can and kept pressing the pedal while making sure the reservoir on the master cylinder had enough fluid. I did each line, one by one.
You just don't flush out the old fluid inside the ABS module.When not activated the ABS module is totally blocked off from the hydraulic system so it's like it's not even there.

Now if you have a '06+ KJ the above is false since those have ESP and the ABS functions a lot more then you think so that little fluid inside that module will get mixed with the new so just do a 2nd flush a few weeks after the 1st for '06+ KJ's for a complete flush without needing to activate the ABS via scanner.


Got it, thanks a lot! Since I have an 05 with no esp, I may need to open the solenoids to do this property. This is why I asked. This is a dealer only drb3 or there are other scanners that can do this?
Author:  dirtmover [ Fri Apr 17, 2015 7:58 am ]
Post subject:  Re: Brake bleeding after caliper change
Yeah, as others have pointed out a conventional flush can leave a lot of fluid in the system. It's a bit like doing a tranny fluid change by dropping the pan. You end up leaving a load of fluid in the TC.

Some of the tools aimed at "pro" shops provide support for ABS bleeding, tranny quick learns, resets etc. e.g. the Snap-On Solus. Of course you're talking big bucks for one of these solutions.

Maybe more frequent flushing coupled with regular exercising of the ABS is a cheaper and more convenient option.
Author:  BodhiBenz1987 [ Fri Apr 17, 2015 4:52 pm ]
Post subject:  Re: Brake bleeding after caliper change
Thanks for the replies, guys. So if I'm understanding correctly, the ABS bleed is necessary to completely flush the system, but not necessary to get the air out of a new caliper or hose to make the system functional?
Because I was under some time restraint, and I wavering in confidence, I ended up letting the dealer do it ... they did let me bring in NAPA parts which saved money but now I regret the $200 I'm spending on labor. For some reason I just lack confidence with this car ... also need it roadtrip-ready soon and can't take chances.
That said, I will want to be able to do my own bleeding in the future ... probably going to change the front hoses out at some point, so if I can use the Motive bleeder with confidence, that will be good going forward. When I mentioned that to the service manager he said they don't recommend it because of too much pressure on ABS seals ... isn't this true of any ABS car, so you just keep the pressure low? What pressure should I limit the pump too?
Author:  Squeeto [ Sat Apr 18, 2015 3:04 am ]
Post subject:  Re: Brake bleeding after caliper change
BodhiBenz1987 wrote:
What pressure should I limit the pump too?


I do mine at 10psi working from the farthest wheel to the closest.
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