I am still chasing a solid brake pedal in my truck. I had a local shop bleed it and they swore there was no air in the system but I'm not convinced they properly purged the modulator. I don't own a rovacom so I have no way to activate the pump and solenoids through the SLABS computer but in looking at the modulator schematic and the SLABS pin layout I think there may be a way to do this without one.


I have a pressure bleeder that I built using a pump sprayer. If I hook that up to the master cylinder and then activate the appropriate solenoid as I bleed each wheel I should push fresh fluid through each passage, correct? The outlet solenoids are controlled by the feeds from pins 1, 4, 7 and 10 out of connector C0506 at the SLABS ECU. Couldn't a momentary contact switch running off the battery be used to trigger each of these? Just want to know if anyone has any experience or input on this before I give it a shot.

 

i would offer you my hawkeye but it is out being repaired and updated, sorry

 

does this help at all http://inform.wabco-auto.com/intl/pd...30/815_430.pdf

 

Version 6 is soon to be out, is that what's being put on it?

 

yes, but they gave me a code for my p-38 & it somehow erased all my DII programming

 

I looked over that attachment from WABCO and it is consistent with what I was thinking except the bleeding procedure does not mention anything about cycling the system to bleed the modulator. None of the WABCO stuff I could find online described that either. All of them just cover normal bleeding. Where is the WABCO procedure for bleeding the modulator?

 

Hi... take a look to this document..read complete...it has a lot info about abs common problems in rovers

ABS Mod - LAND ROVER CLUB V.I.

pay attention in the 14C, 14D and 14E... tells how to bleed and activate the abs...

hope this can help...

 

I've read about activating the ABS or HDC to purge the air from that side of the modulator and it makes sense but I prefer the idea of opening the solenoids and forcing the air out while I have the bleeder open on the caliper. It's instant gratification.


I'm just going to go the HDC route for now and see if it works. What's a couple more quarts of brake fluid at this point?

 

Bleed the lines as they come out of the modulator and then bleed at the calipers. This should get most of the air out.

 

Based on my review of the schematic in RAVE and in the WABCO literature, it appears that there is a portion within the modulator where the fluid is isolated from the braking system via solenoids and non-return valves where the fluid is pressurized and moved only by the return pump. The only way to get any air out of this portion of the system is to activate it, which is what bleeding with testbook, Hawkeye and Faultmate, etc. all do. This circuit is also activated when the HDC operates.


I really have no idea what this brake system has gone through prior to my owning it. There are no lights on the dash at 108,000 miles so the modulator may have been dealt with before. The lines were changed over to SS extended ones before I bought it so it was bled then, and the fluid looked fairly new when I got the truck at 80,000 miles. I have also flushed the fluid using a vacuum bleeder and had it done with a pressure bleeder and yet the pedal still feels like crap so at this point I think I'm left with trying to bleed the modulator then the lines again.