ABS DTC code 51

[Heelerdude]

Update, edited with correct terminology.

Big Shout out to @Jpoole, I Fixed my ABS this weekend using his method of removing the stator housing from the ABS pump and cleaning out the rust particles that were jamming the motor. So first I obtained a used unit that was locked up so I had nothing to loose, removed that stator housing from the motor and yup, it was rusty enough to jam the motor but not horrible, cleaned it all out and reassembled and success! When bench tested by jumping the harness I got it to spin over....Ok, now onto the vehicle....I still didn't want to break into the system so my goal was to see if it was possible to perform this procedure on the truck without removing the ABS Unit, I can happily report that yes, it is possible to perform this repair in the truck without breaking into the system requiring a re-bleed. I removed the Evap can and bracket, unbolted the relay box and swung it out of the way, all ABS bracket bolts and the 3 isolator nuts. disconnected all harnesses and was able to lift the pump up and swing it inboard enough to be able to get a small screw bit on a 1/4 inch ratchet and undo the stator housing and pull it off. once removed and hanging there I had enough slack to flip it up and clean it all out...here's where it gets interesting, My existing housing that holds the brush assembly on my truck was really rusty to the point that the brush holders fell off leaving me with a bad housing...well that sucks....now what? so I carefully unpinned the 2 large wires that are the only thing going to the rectifier case and swapped the rectifier with the used unit I got working since it was in way better condition. the hardest part as mentioned in a previous post was getting the brushes to stay put while slipping the housing back over the armature. in the end I positioned each brush in it's spring holder and zip tied it in place till I had all 4 in position, Then I cut a 1"x4" strip out of a milk jug and rolled it into a tube that would be rigid enough to hold the brushes in place but thin enough to slip over the armature and pull it out from the access hole. Once in place I clipped the zip ties and let the plastic tube hold everything in its spot. This almost worked and I got it on but a couple brushes slipped out but i was able to move them into position with a small pick without having to slide the housing off and start over. This was trial and error and prolly took the longest of the whole project. I got everything buttoned back up jumped the motor again and it spun over so I plugged everything back in, Started it up and Boom Shagalaga!!! no ABS light!!! Took it for a spin and it stayed off, I even tested the system by stopping hard on gravel and the system worked giving the tell tale pulsating pedal. I will report later if the light comes back on but for a code "51 ABS motor Locked" I can't see why this wouldn't last unless some other debris got in there. Again best part is I didn't have to open the fluid side. Hope this helps others facing the same dilemma. Cheers!!

 

[jpoole]

Well done! I'm glad to learn this can be done without breaking a line and forcing a re-bleed.

Next person that needs to fix this issue gets to take photos of the process

 

[Heelerdude]

Well done! I'm glad to learn this can be done without breaking a line and forcing a re-bleed.

Next person that needs to fix this issue gets to take photos of the process

I got one more to go, I will video the whole process!!

 

[bonestock]

I have ABS parts available in Chattanooga, TN if there’s a need. ully functioning when removed. Complete bits from a full delete. From the brake lines to the pump to the wheel speed sensors, wires, LSPV; all of it. No rust. No use.

 

[jpoole]

@bonestock Not sure who your comment is aimed at but if you are looking to give those parts away let me know and I'll be glad to add them to my spares collection.

 

[Erotictaco]

I have ABS parts available in Chattanooga, TN if there’s a need. ully functioning when removed. Complete bits from a full delete. From the brake lines to the pump to the wheel speed sensors, wires, LSPV; all of it. No rust. No use.

I have a couple codes for ABS including a broken wire plug on the front harness throwing an open circuit and now a code 51 for the pump. Id gladly take the pump, front harness and front wheel speed sensors off your hands

 

[bonestock]

I have a couple codes for ABS including a broken wire plug on the front harness throwing an open circuit and now a code 51 for the pump. Id gladly take the pump, front harness and front wheel speed sensors off your hands

Shoot me a DM and we can go from there.

 

[98 SNAKE EATER]

JPoole, Nice fix, How did you hold the brushes back into their slots when re-installing the armature? Seems like that would be a major PIA.

19mm thinwall socket does the trick

 

[98 SNAKE EATER]

19mm thinwall socket does the trick

 

[thelal]

My relay and ground look fine. I checked the front sensors and those seem to ohm out correctly. Wish there was an easy way to check the actuator, like applying 12v somewhere.

Is there a confirmation on how to give the motor a 'spin' (jolt) ; just in case I have it wrong (with the 4 earths and 2 12v+) from the other post

 

[98 SNAKE EATER]

Is there a confirmation on how to give the motor a 'spin' (jolt) ; just in case I have it wrong (with the 4 earths and 2 12v+) from the other post

To spin the motor, you only need these two leads for positive and ground

The other grounds mentioned are to activate each of the flow solenoids (not necessary when testing just the motor)

Keep in mind, if you're bench testing a unit that isn't mounted in the vehicle, you'll also have to add a ground wire to the body of the pump itself

 

[thelal]

To spin the motor, you only need these two leads for positive and ground

..

Getting a spark now but no movement. tried tapping the motor casing as tip on/off the lead. no joy
guess will have to take it apart and dismantle.
Any things to look out for ?

 

[jpoole]

I would try to do the cleanup without breaking any brake lines so that you can skip doing a full system fluid flush/bleed. @Heelerdude describes pulling this off above. Other than that it seems likely that you just need to remove the rust scale, take steps to minimize rust moving forward and you'll likely be good to go.

 

[Heelerdude]

View attachment 3996487

Yeah that will work holding them in but you still have to get it over the armature and you can’t do that with the socket in there. I ended up cutting a strip out of a milk jug and rolled it into a small tube. it was rigid enough to hold them in place but thin enough to allow it to slip over the armature and then pull out through the center hole with the rubber cover to let the brushes slip into place. I did all this with the pump Assy still in the truck with all brake lines intact.

 

[thelal]

.... I did all this with the pump Assy still in the truck with all brake lines intact.

Scratching my head figuring out how you managed to take the motor cover off and manipulate it with ABS unit in place. No room between fender and cover . Maybe an inch or two with relay takem out.

Does the unit flex and have ability to move it around once bolts loosened etc even with brake lines still attached. Mines a 97
Thanks

 

[Heelerdude]

Scratching my head figuring out how you managed to take the motor cover off and manipulate it with ABS unit in place. No room between fender and cover . Maybe an inch or two with relay takem out.

Does the unit flex and have ability to move it around once bolts loosened etc even with brake lines still attached. Mines a 97
Thanks

With all the bolts removed and the fuse/relay block unbolted and swung away I was able to flex it inboard enough to get a small 90 deg angled ratchet screw driver with a JIS bit in it and get the cover off. It just has to swing in and rotate up enough to get the cover off. The hardest part is getting it back on with the brushes in place. That part took longer than the whole disassembly and cleaning process.

 

[98 SNAKE EATER]

Yeah that will work holding them in but you still have to get it over the armature and you can’t do that with the socket in there. I ended up cutting a strip out of a milk jug and rolled it into a small tube. it was rigid enough to hold them in place but thin enough to allow it to slip over the armature and then pull out through the center hole with the rubber cover to let the brushes slip into place. I did all this with the pump Assy still in the truck with all brake lines intact.

Done it plenty of times

I just leave the socket in to hold the brushes and let the armature push it out of the inspection hole while lowering the endbell into place.

All 4 brushes snap onto the comm instantly.

Here's a short video on a junkyard pump

 

[98 SNAKE EATER]

With all the bolts removed and the fuse/relay block unbolted and swung away I was able to flex it inboard enough to get a small 90 deg angled ratchet screw driver with a JIS bit in it and get the cover off. It just has to swing in and rotate up enough to get the cover off. The hardest part is getting it back on with the brushes in place. That part took longer than the whole disassembly and cleaning process.

When cleaning, I use a few small zip ties to hold the brushes in place, then just blow everything out with compressed air

 

[Heelerdude]

Done it plenty of times

I just leave the socket in to hold the brushes and let the armature push it out of the inspection hole while lowering the endbell into place.

All 4 brushes snap onto the comm instantly.

Here's a short video on a junkyard pump

Beautiful!! My socket was just barely too thick to fit through the inspection hole!! Awesome tip, i used the zip tie method as well for the cleaning process.