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replaced MC, litle soft.

Old Aug 5, 2012 | 12:29 PM
  #1  
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pwb
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From: Norway
Year: 1993
Model: Grand Cherokee
Engine: 4.0L I6
Default replaced MC, litle soft.

This weekend i replaced the break MC and both front calipers, dust shield and hub bolts. I have ABS but i only bleeded it manualy, do i need to cycle/run the ABS pump, i replaced the calipers first and bleeded them, so the ABS pump hasnt been empty. When replacing the MC i bleeded it on the lines that get from the valve to the ABS pump. I havent had time to bleed the rear breakes, but i will do that before i use it. But on a testrun the breakes works okey and i cant push it to the floor, but its seems a litle soft, is that beacuse not bleeded the rear or is there som air in the ABS pump?
I used this MC http://wheelbearings.ca/brakes-wheel...-cylinder.html
But the reservoir is inline with the cylinder so when filling it i cant get to max since all the fluid is in back of the reservoir, is this a problem? Could i replace the reservoir with the one i got on my old one since thats more tilted?
This was my first time replacing mc and calipers, its not hard/difficult if someone wonder.

Last edited by pwb; Aug 5, 2012 at 12:32 PM.
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Old Aug 6, 2012 | 12:56 AM
  #2  
jnicewan's Avatar
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From: Norman, OK
Year: 95
Model: Grand Cherokee
Engine: 4.0
Default

Air can or may pass through the ABS hydraulic unit but you may need to bleed the 4 lines that go into it. You would bleed these 4 lines just like you would bleed the calipers other than you are loosening the actual lines instead of a bleeder screw. There is no order to doing it but all 4 of them should be bled.

The bleeding sequence is MC, ABS unit (aka HCU) at the 4 brake lines, right rear, left rear, right front, left front. Most people dont ever bother with bleeding the ABS unit so you can use your judgement if needed.
Also when bleeding the calipers/cylinders it can help to tap the caliper or wheel cylinder to insure that air bubbles are not stuck to the sides. Tapping them with a wrench or screwdriver handle will make the air bubbles travel to the top and through the bleeder (hope that makes since) Anyway you do need to bleed the rear brakes or whole system when doing a MC.
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Old Aug 6, 2012 | 01:07 AM
  #3  
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pwb
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From: Norway
Year: 1993
Model: Grand Cherokee
Engine: 4.0L I6
Default

Originally Posted by jnicewan
Air can or may pass through the ABS hydraulic unit but you may need to bleed the 4 lines that go into it. You would bleed these 4 lines just like you would bleed the calipers other than you are loosening the actual lines instead of a bleeder screw. There is no order to doing it but all 4 of them should be bled.

The bleeding sequence is MC, ABS unit (aka HCU) at the 4 brake lines, right rear, left rear, right front, left front. Most people dont ever bother with bleeding the ABS unit so you can use your judgement if needed.
Also when bleeding the calipers/cylinders it can help to tap the caliper or wheel cylinder to insure that air bubbles are not stuck to the sides. Tapping them with a wrench or screwdriver handle will make the air bubbles travel to the top and through the bleeder (hope that makes since) Anyway you do need to bleed the rear brakes or whole system when doing a MC.
ok, thanx. When the shop bleeds the ABS they cycle/run it, where does the air goes? does it goes up to the reservoir with the tubes that goes from ABS pump up to the reservoir? If i drive it on loose gravel and brakes so the ABS starts, would that do the same thing?
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