WClark

I replaced the stock rubber flexible brake lines with teflon/steel braded jacket lines last week and replaced the 1 year old OEM fluid with Motul 600. I let the fluid reservoir go down to near empty when replacing the lines, then bled all 4 corners per the manual and well as the clutch. I used a vaccum one man bleeder (from Griots) and put about 2 containers of Motul in during the first bleed.

I tested the brakes and the pedal felt a little squishy so I re-bled the brakes. I am not convinced it made any difference. One observation I have on the bleed process is the brake bleeder seems to suck a lot of air when doing the caliper bleeds. When it was on the clutch bleed it didnt suck air (only fluid) into the bleed line and when I used this tool on our GSX it didnt either. I am pretty sure it seals well arounf the bleed nipple but I might be pulling air around the threads of the bleed screws - could that keep me from getting all the air out of the system? Should I get a pressure bleed system instead?

So I am either still looking at some air in the system or the Motul doesnt feel as firm as the OEM fluid.

Anyone have any experience with Motul, wisdom to share on the bleed tool or advice as to what to do now?

Sharon

Type of fluid isn't going to make an impact here. I think that you probably introduced a lot of air by letting the resevoir go down so far. I bleed my brakes the old fashioned way (bribing someone to pump the brakes), and never let the resevoir get low. Also, be aware that the ABS system traps a lot of air.

When installing new brakes, or doing a major flush, it's not that unusual to need to bleed more than once. One thing I found helpful is to do the initial bleed, then hop in the car and exercise the brakes some (getting into ABS). Head back to the garage and bleed again. Bleeding the brakes warm (e.g., mid day at the track) gets the best results IMHO.

Audiboy

If you are doing it manually (as in pump/pump/hold) keep engine running. At the pressures the brake system is applying, liquid is incompressible so if it feels squishy, that's air.

The only one man bleeders I trust are the pressurize ones. If don't have one, invite friend over for a one legged workout. Don't worry, it'll be fine, just don't let fluid out too fast and all of it to make it come down too low. If this method breaks M/C's oooh I'm in trouble as me and my GF and been doing one legged workouts for years

WClark

...As I understand the system I need to force the ABS to activate at least once to move fluid thru there. The manual doesnt suggest a bleed method for that except to get it to activate - and if need be re-bleed. The roads are wet this morning so I will go out and scare the crap out of my neighbors...

I didnt let the whole system go dry but the reservoir did get very low so some air may have gotten in at the supply end before I refilled. I will use the open-pump-close-release method this time rather than hunt down a pressure bleeder. I can probably bribe the SO to help out.

DougR

I am seriously vague on the specifics, but there's a sequence to follow where you open the bleeder valves in turn, and the computer runs the ABS pump to do the bleed for you. I'm not sure, does the '01 A4 have ESP? You can probably track down the details by searching, don't remember whether on this forum or on Uwe's VAG-COM list...

WClark

I was able to get the ABS to activate yesterday when the streets were wet.

I re-bled the brakes a little later using the pedal pump method and things seem to have firmed up significantly.

DougR

Excellent, glad to hear it (and glad to learn of the ABS aspect for my own bleeds!)