Hi SocalSam and all.

There are 2 separate issues.

Issue #1 'soft' braking -should be air in the system.
Hell knows why bleeding is so complicated.

Issue #2 motor/pump is coming on every second time I hit the brake and
this does not seems right.
reason could be the accumulator low on nitrogen.

#2 also can lead to the situation in the extreme when the brake must be hit several times hard and the booster has not time to build up and store pressurized fluid...so pressure drops below the minimum and the alarm goes off.


I was driving very slowly the last days because of the alarm issue (I need the car and it is too cold right now to work on the brakes).
When I am driving defensive there is no alarm.

Another test is the car in park and I hit the brake several times... say after 5-10 pushes on the brake the exact alarm goes off.... after 15 seconds it is silent again....as the pressure recovers.


What is happening inside the system. I was thinking..... if there was no air in the the lines (as it should be) there would be almost no flow of brake fluid in the lines at all (because fluid is not compressible) and this less pressure loss during braking? meaning the accumulator would last longer?
I am not sure about this but it might be this way.

The other option would be that there is simply not enough pressure stored... in case the accumulator lost tpp much gas (which is typical for membrane accumulators).

This is the only connection between #1 and #2 if at all true.

For #1: soft braking: I have bled the master cylinder.... when I installed the rebuilt pump and accumulator.
Normally after the MC build up pressure and pump.... then the bleeding is all up to the ends of the 4 lines: bleeding at calipers. Any remaining air from the MC would then come out at the end of the lines after enough fluid is pumped through.

I have not revisited the MC bleeding for that reason... but you said there might still be air trapped that would not come out at the calipers?

See if air from the MC would come out by bleeding the MC (cracking the 4 lines to the 4 calipers) then the air would come out as well at the calipers.
Or did I miss something?


dragging calipers:
I know that one of the T4R issues are dragging calipers.
I have rebuilt the calipers maybe 4 years ago and the brakes were great after that.... and the brakes have become increasingly softer since then.

This means I had the soft brakes way before my initial incident last fall with complete failure of the brake booster during the event when one of the rear brake lines failed (rusted out rear brake line). I repaired the brake line and installed a rebuilt booster motor/pump/accumulator.

Could there be a third issue with the brake calipers causing 'soft' braking?
Maybe it is not the 'air' after all?

Sorry for the lengthy text.

Martin