When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I did not get a chance to test the rear this weekend. Spent MUCH more time than planned on replacing ABS pump unit.
1. Porsche, once again, made removal/replacement much harder than required. A few minor changes to the bracket, 928.355.041.02, and it would have been easy to slide unit out of the wheel well. But, because they are spiteful jerks, it was a complicated puzzle box dance that required a lot of extra removal under the hood.
2. Then getting it back connected, the below brake line was a HUGE PITA to get reconnected:
Ken,
Do you have the "barrel grommet" off an old sensor you could send me? I may be able to cast a new one out of rubber you could slip over the new wire (before attaching the new connector) or if you have the new connector installed already you could just split it lengthwise and put it on the new wire.
Ken,
Do you have the "barrel grommet" off an old sensor you could send me? I may be able to cast a new one out of rubber you could slip over the new wire (before attaching the new connector) or if you have the new connector installed already you could just split it lengthwise and put it on the new wire.
have a car in the shop with ABS LIGHT on, bad rear sensor.....for now, we split the signal from the known good sensor in the rear to feed the signal for both rear sensors to the control unit and that worked....looks like you can modify the rear sensor from a later 928....cut the metal upper piece off and seems to be equal to the length of the old sensor....the oring was even on it.....car had to leave so we did the wire trick and light stayed off ....
Guys just finished test driving new front sensors in the early '86 using the part Ken does above...I have ABS for first time in honestly 3 or 4 years??
Its dry outside right now so the testing I've done has been limited...but it's definitely working again.
I used a butt splice connector from old to new sensor and loads of vaseline and pulled the new wire up so it traces the same path....I use junior timer type terminals into Molex connectors..not as good looking as Mr. Rudd...I was a little paranoid about dust / etc getting to the terminals from the back so used friction tape around the whole thing and the nice thing there is it makes a nice grippy surface and the connection slides right into the same clip
I took my time...did it over a few days...don't try to do the first one all at once and don't do it when you're tired...the process to pull the wire takes a little patience and maybe a couple back and forth trips from the top of the engine to where the sensor wire goes into the wheel well but they work.
Ken thanks for the hard work! So glad to have ABS again!
The worse news. It simply did not work, ABS warning light came on after a few feet.
Testing at ABS controller connector showed about 1,200 ohms across each sensor, so I knew I had good connectivity.
I hooked up the Oscilloscope across the rear sensor pins in the connector and went for a drive:
-rear, left between term. 8 and 9
-rear, right between term. 24 and 26
Flat line, no measurable signal:
For comparison, the fronts ( Pins 4+6 and 21+23 ) return this:
My theory is that the Volvo sensor I an using for the rear is set up to sense a pulse/signal along the "edge" of the bar, like the front sensor, not across the tip of the sensor, which is where it would be on the rear.
The search continues, and I welcome input, suggestions, theories.
I agree with Ken that the Volvo part ABS264 does not work on the rear. Fitted it last weekend after filing the screw hole out with a chainsaw chain file. ABS light comes on after the vehicle starts moving.
Resorted to repairing the ABS sender using the John Madden method described. ABS back to working. I suspect there is a good possibility that the Volvo front ABS unit may work once cut down to the right length. Next time the rear fails will try the Volvo front cut down.
The sensor that looks like it may have the best chance of fitting is off a mid-80's Mercedes 380SL. Problem is that, while I might pay the price if it actually worked, they are WAY too expensive for me to hack up as test subjects that may not work. Seem to go for between $300 and $450 each.
03-19-2018, 12:04 PM
