1985-1998 [Subscribe to Daily Digest] |
 | [Main 9000 Bulletin Board | BBFAQ |
Prev by Date | Next by Date | Post Followup ]
Member Login / Signup - Members see fewer ads. - Latest Member Gallery Photos
Re: Replacing ABS system (long) Posted by Ari [Email]  (#2847) [Profile/Gallery]
(more from Ari) on Thu, 3 Apr 2003 13:36:21
In Reply to: Re: Replacing ABS system (long), Shaun  [Profile/Gallery]
, Thu, 3 Apr 2003 07:52:12
Members do not see ads below this line. - Help Keep This Site Online - Signup
|
Pin 85 is the ground pin on the relay, as you already know. Pin 86 is power. When you grounded 85, the relay closed, and the pump turned on. There was no need to replace the relay, because it was doing exactly what it should be doing.
So yes, the relay isn't getting a command to turn on. The relay gets a low pressure command from the pressure switch. It should be a pretty simple matter to check the wiring. With low pressure, the low side of the relay (85) should be connected to ground through the pressure switch. If it isn't, you should be able to measure across the switch to see if it's closed, or the problem is a bad ground somewhere.
Townsend has a schematic of the system. Yes, they're down right now, but they'll be back up sometime.
The problem with the manual switch is that you don't know when the system is fully pressurized - you can't tell 180 bar from the driver's seat. So a few things may be going on. Maybe you aren't running the pump long enough, so it only seems like the pressure drops quick. Or you ran the pump too long, the pressure ran too high, and that high pressure ruptured the diaphram in the accumulator.
The 'right' way to test the accumulator is to get the system pressure up to 180 bar. This is usually done by letting the pump run until the pressure switch shuts it off. You can't do that. But assuming you have 180 bar of pressure, you then hit the brakes very fast and very hard. If the Brake Fluid and ABS light come on after 3-5 pumps, the accumulator is bad. If it takes 12-15 pumps, the accumulator is good.
The ABS and Brake FLuid lights go out at 134 bar. The pump should shut off at 180 bar, and come back on at 140 bar. My guess is that you're turning the pump off just after the lights go out, which is barely above 105 bar, so yes, the lights come back on quickly.
Since the lights do go on and off, the grounding to the pressure switch is correct, and at least part of the pressure switch is correct. I wonder about the wiring from pin 4 of the pressure switch to pin 85 of the pump relay.
Really, with a copy of the schematic this should be a trivial troubleshooting job. You might have a bad ABS module, but it appears that the pump and relay are fine. Once you get this pressure switch issue figured out, then you can see if the accumulator is OK.
If you can't get the schematics from Townsend, post back, and maybe I can find a way to email them to you.
Good luck!
posted by 192.249....
, Wed, 2 Apr 2003 13:47:29, Thu, 3 Apr 2003 07:07:14, Thu, 3 Apr 2003 07:52:12, Thu, 3 Apr 2003 13:36:21 <-- Viewing This Message, Fri, 4 Apr 2003 14:43:51, Wed, 2 Apr 2003 19:01:08
No Site Registration is Required to Post - Site Membership is optional (Member Features List), but helps to keep the site online
for all Saabers. If the site helps you, please consider helping the site by becoming a member.
 |
 |
 |
 |
 |
