Question regarding replacement of ABS Pump and Bleeding System

[don40vette]

After replacing my ABS pump with another unit do I need to bleed each caliper with a power bleeder and then bleed ABS pump using INPA or is the power bleed not necessary and just bleed the system using INPA?
Thanks for any input

[tsk94]

I believe just bleeding the system with INPA is enough. But start with the INPA bleed and you can manually bleed them after just to be certain, if you want.

[don40vette]

Originally Posted by tsk94

I believe just bleeding the system with INPA is enough. But start with the INPA bleed and you can manually bleed them after just to be certain, if you want.

I think this is the best way to go. If the brakes arent feeling normal then power bleed after bleeding using INPA.

Since I have never used INPA before this will be my first go with it. The videos I have watched look like the RIGHT REAR has around 6 ounces bled from it. Dont know if each each of the other brake lines have less bled since they are shorter runs.

I did a little calculating with amounts of fluid in tubing. One foot of 1/4 inch inside diameter tubing holds 0.3264 ounces of fluid.

Based on that, I am estimating the Right Rear tubing to be 16 feet long on a E92 M3 Coupe which would hold 5.22 oz of brake fluid.

Based off that it seems like the INPA bleed procedure is giving it a full bleed.

Also, doing some additional guesstimating LR @14 ft, RF @ 6ft, and LF @ 3ft it takes less than 13 ounces to bleed the whole system.

If any of these calcuations are close at all, the INPA procedure does a complete bleed and a power bleed before or after is just wasting time and money.

As I said, all this is ballpark figures so those that are in the know, go easy.