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-   -   Bleeding ABS Brakes (http://www.skoolie.net/forums/f37/bleeding-abs-brakes-18120.html)

bstewrat3 06-09-2017 08:32 AM

Bleeding ABS Brakes
 
I just replaced the master cylinder on my 2001 International Amtran and while reading the directions on my vacuum tool it had a warning about ABS brakes being potentially hazardous if they are bled wrong. I had never considered this before on other vehicles, but don't want to mess up anything. Has anyone here bled they're bus brakes and did you have to do anything special? My ABS is a Kelsey Hayes 410M, but I haven't found any good info yet.

leadsled01 06-09-2017 08:38 AM

Ya, on cars I just drive it in gravel and lock the brakes up so the abs module activates and you hear the ratchet noise. Do this several times and rebleed the brakes after each time. A bus on the other hand , well good luck with that method.
Quote:

Originally Posted by bstewrat3 (Post 208041)
I just replaced the master cylinder on my 2001 International Amtran and while reading the directions on my vacuum tool it had a warning about ABS brakes being potentially hazardous if they are bled wrong. I had never considered this before on other vehicles, but don't want to mess up anything. Has anyone here bled they're bus brakes and did you have to do anything special? My ABS is a Kelsey Hayes 410M, but I haven't found any good info yet.


Rusty 06-09-2017 09:26 AM

Lock em up !
 
Quote:

Originally Posted by leadsled01 (Post 208042)
Ya, on cars I just drive it in gravel and lock the brakes up so the abs module activates and you hear the ratchet noise.

Works good to trick the ABS into actuating and bleeding the air out. Wet grass or icy road works just as well. Brakes need to lock, pedal needs to pulse.

Probably not in the Service Manual tho...

Stu & Filo. T 06-09-2017 11:33 AM

Best luck I've had bleeding brakes is using a pump that connects at bleeders & pumps fluid back to the master cylinder .

bstewrat3 06-09-2017 02:16 PM

Quote:

Originally Posted by Stu & Filo. T (Post 208080)
Best luck I've had bleeding brakes is using a pump that connects at bleeders & pumps fluid back to the master cylinder .

I don't know if the ABS controller is going to let that happen. I guess I'll just take it for a drive and see if I can work the bubbles through and bleed it a couple times unless a better method comes along before then.

bstewrat3 06-12-2017 02:17 PM

Just to follow up here is how things worked out.

I was able to find the remanufactured master cylinder at O'Reilly Auto Parts for $114 which beat the $440 for a new one from International. I bench bled the new master using the included plugs for the brake line ports prior removing the old one. When I disconnected the old brake lines I made sure the opening was always the highest point to avoid any leakage of the fluid which was right at the opening. Once the new master was bolted up I removed the bleeder plugs one at a time and connected the brake lines quickly to avoid leakage. Once the install was complete I decided to see how spongy the brake pedal was before bleeding and found no softness at all, so I cautiously drove it to a large vacant lot near my house to do some hard stops. I did several stops forward and in reverse and had no issues, so I decided to not mess with a good thing and try bleeding through the ABS system. I took it on a 400 mile road trip yesterday and everything is still good. It may not be the recommended process, but it so far has worked for me.

Rusty 06-12-2017 02:30 PM

Very Good News !

I've learned to savor the victories (reasonable parts procurement, successful installation) so as to reduce the sting of defeats.

Sometimes You Eat the Bear, and Sometimes the Bear Eats You.


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