[jvanabra]

The clicking is normal. When you hit the brakes the APC solenoid returns to base boost, and when you take your foot off the pedal the solenoid goes to full boost. That is expected and correct behavior.

A hot relay can also be caused by a device drawing too much amperage across the relay. For example, a seized motor might cause a relay to get hot. In this case - and I'm not saying this is the case - it could be a bad pump motor drawing excess amperage across the relay causing it to get hot.

I don't have one to look at, but IIRC the ABS relays are special like the fuel injection relays. They are pseudo DPDT relays and not commonly available. Wait, I might have one to check.

 

[jvanabra]

If my 9000 is the same as a 900 then I'm wrong and they are just standard relays.

 

[newellsb-saab]

If my 9000 is the same as a 900 then I'm wrong and they are just standard relays.

If my 9000 is the same as a 900 then I'm wrong and they are just standard relays.

The clicking is normal. When you hit the brakes the APC solenoid returns to base boost, and when you take your foot off the pedal the solenoid goes to full boost. That is expected and correct behavior.

A hot relay can also be caused by a device drawing too much amperage across the relay. For example, a seized motor might cause a relay to get hot. In this case - and I'm not saying this is the case - it could be a bad pump motor drawing excess amperage across the relay causing it to get hot.

I don't have one to look at, but IIRC the ABS relays are special like the fuel injection relays. They are pseudo DPDT relays and not commonly available. Wait, I might have one to check.

Thanks for the information. At least that is not another thing to add to my list of things not working.
Yeah I could of swore when I first got the car the pump was working but now it is not. I am going to have to test the pump to see if it is getting power and if it is then see if I can by pass the connection to test if the pump works or if not doesn't then get a replacement one.

Is there a easy way to test the pump and pressure switch?

I can tell someone else was in there trying to figure out what was wont with it so that worries me a little.

 

[jvanabra]

It's a very simple system overall. Check the wiring diagrams and you will see the very few pieces in play here.

 

[newellsb-saab]

Thanks

 

[Dick S]

Couple pics of the GM 25676065

Hi V-22 Osprey, were you able to find out how old the GM part was. As I understand it, they were used on RHD Cadillacs, etc from the 2000 timeframe. There could not be that many made. Also, do you know how many brake presses you get before the pump comes on. I am trying to put this in a 93 9000. Thanks!

 

[Dick S]

Thanks for the information. At least that is not another thing to add to my list of things not working.
Yeah I could of swore when I first got the car the pump was working but now it is not. I am going to have to test the pump to see if it is getting power and if it is then see if I can by pass the connection to test if the pump works or if not doesn't then get a replacement one.

Is there a easy way to test the pump and pressure switch?

I can tell someone else was in there trying to figure out what was wont with it so that worries me a little.

I am with you on the challenge in testing the system in situ. I just built a test system to evaluate spare pumps, accumulators and switches outside of the car. I have wired in LEDs and put a pressure gauge and drain valve so I can let the pump pressurize the system, see when the switch contacts (3 sets) open and close. I can lower pressure to see the switches operation in that direction. I can also see what the accumulator pressure is. I have yet to fit it to the car, as I expect that will take some time and require re-bleeding. But accumulators come off easily and I could see my best one was at 30 bar, one was 20 and two were essentially flat (spec is 40-80).

 

[jvanabra]

That's pretty awesome - post some photos!

 

[Dick S]

Thanks for the information. At least that is not another thing to add to my list of things not working.
Yeah I could of swore when I first got the car the pump was working but now it is not. I am going to have to test the pump to see if it is getting power and if it is then see if I can by pass the connection to test if the pump works or if not doesn't then get a replacement one.

Is there a easy way to test the pump and pressure switch?

I can tell someone else was in there trying to figure out what was wont with it so that worries me a little.

Here is a schematic of a 9000 which I believe is the same as a 900 including wire colors. The component outline at the bottom (pins 53, 51, 8, 50) are the ABS module. The pressure / warning switch is 294. Contacts 4-1 close when the pressure drops below 140 to ground the coil of the pump relay 293, which close the contacts 30 and 87 to start the pump motor. They open at 180 bar to stop the pump motor. Contacts 2-1 are for the ABS (pressure) warning light. They close at 105 bar to turn the light on and open at 134 bar to turn the light off. Contacts 3-5 work oppositely 2-1 by closing at 134 bar and opening at 105. The service manual is not clear on their exact function but I suspect it is a redundancy for the warning light contacts other they are inverse in function. So can you test a pressure switch.

Probably the first thing to check is see if the 30A fuse FC1 is blown in the fuse box as that delivers current to the pump. This may be different for a 900 but there will be a fuse for sure. You can certainly see if contacts 4-1 of the pressure / warning switch are closed to allow the pump to run. Do this by having the ignition off and pressing the brake pedal 20 times to make sure some pressure has been bled off the system. Then pull the ABS relay (p/n 95 22 822, it will say SAAB Ate on it). Measure the resistance between the receptacle that blade 85 of the relay goes into (marked 5 on the schematic) to ground. It should be only a few ohms of resistance. If this checks out ok, there may be a problem with the relay or 30A FC1 fuse could be blown, or wiring somewhere. With relay still out, you could to jumper the receptacles that Pins 30 and 87 of the ABS relay go into, that should turn the pump on. The arrangement of these two pins are diagonal on the 2 x 2 blade grid rather than side by side so be careful. Be ready for a spark, as this is 12-15A.

If the pressure switch resistance checks out and you can jump the relay contacts to start the pump motor, I would suspect the relay itself. Let me know if you have questions.

 

[jvanabra]

Sorry, I meant your tool... Gauge, LEDs etc.

 

[Dick S]

That's pretty awesome - post some photos!

Ok, here are the usual caveats. The SAAB ABS system works at pressures in excess of 180 bar/ 2600 psi. These are hydraulic pressures so all fittings, gauges, etc. must have working pressures well beyond this for safety. I used set mine up with a blast wall in case there was a problem. A hydraulic leak at any joint can pierce the skin, blind you, etc. If you build one of these or mess with your system, DO SO AT YOUR OWN RISK.

Attached is a photo of the hydraulics. All fittings are rated from 5000-6000 psi.

On the electric side, I have attached a schematic. It took more work than I originally expected but what doesn't. And the board is not pretty. I powered it from one of those portable car jumpers with a lead acid battery (not the tiny lithium battery ones). The momentary switch allowed me to pulse the pump to slowly build pressure and also acted as an override / dead man's switch in case there was a malfunction of the pressure switch shutting off or the internal bypass valve of the pump not working. I wired in 3 LEDs to give me the status of each the pressure switch contacts. SAAB implements diodes in the ABS circuit and I used a full wave bridge wired to act as a single diode (I did not have a big 10A rated diode) to serve as a flyback diode. This prevents arcing in the relay contacts that would occur when trying to shut off the pump motor. I used connectors to the pump motor and pressure / warning switch cut from a C900.

The accumulator pressure is seen by the immediate jump of the gauge from zero to whatever the pressure of the accumulator is. I got tested 5 accumulators- the original one in my car and two others from the salvage yard were essentially zero. A third was 20 bar and the last one, now in my car, is 30 bar. So I am on the hunt for a replacement (GM, Jag, etc.). The spec is 80 bar new and replace at 40 bar. So I am out of spec but way better than what I had.

If you have Mk II ABS pump issues, PM me and I will see if I can help.

 

[Dick S]

It fit fine. The only issue was/is the amount the brake pedal depressions before the ABS pump activates is too frequent I think. When I first installed it, it took 4-5 times than after bleeding the system it takes about 10 times before the pump activated. From reading previous posts, the number should be at least 2 to 3 times that.

Sabi, where did you source the Bosch unit. They seem to be out of stock most places. Wish to avoid Ebay if possible.

 

[Dick S]

It fit fine. The only issue was/is the amount the brake pedal depressions before the ABS pump activates is too frequent I think. When I first installed it, it took 4-5 times than after bleeding the system it takes about 10 times before the pump activated. From reading previous posts, the number should be at least 2 to 3 times that.

I thought the 30 presses was related to ignition off, how many presses till the pedal felt hard.

 

[wdssaab]

Sabi, where did you source the Bosch unit. They seem to be out of stock most places. Wish to avoid Ebay if possible.

I purchased the Bosch Mercedes Benz unit 0 265 202 070 from e-bay (partsgoat) @ $179 + state tax a week ago, it came within 3 days. Will be installed next week via local SAAB mechanic in my '91 900 SE conv.

 

[jvanabra]

That is a fantastic contraption! Someone should have built one of these 20 years ago. Although, as you point out, hydraulic fluid at 2000+ psi is incredibly dangerous, so maybe this isn't a tool most people should mess around with.

 

[Dick S]

That is a fantastic contraption! Someone should have built one of these 20 years ago. Although, as you point out, hydraulic fluid at 2000+ psi is incredibly dangerous, so maybe this isn't a tool most people should mess around with.

In this forum, someone with username ionsignal did build at least the hydraulic side of this back in 2012. The electrical side is mostly replicating the SAAB circuit, with the addition of some LEDs and the current sense resistor.

 

[Dick S]

.

 

[Dick S]

I purchased the Bosch Mercedes Benz unit 0 265 202 070 from e-bay (partsgoat) @ $179 + state tax a week ago, it came within 3 days. Will be installed next week via local SAAB mechanic in my '91 900 SE conv.

Cool. Please let us know how many brake pedal presses you get before pump turns on. Thanks.

 

[Dick S]

Sabi, where did you source the Bosch unit. They seem to be out of stock most places. Wish to avoid Ebay if possible.

FCP now has the Bosch accumulator for $62.49. At that price I get a vast improvement over my current situation for not much $$. Hope the price sticks...

 

[jvanabra]

Oof. I should go buy one of those for the 9000 Aero.

I did go buy one. That's worth stockpiling. I need an air filter for the 9-3 anyway, so now the air filter ships free.