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Bled the brakes last night and drove it to and from work. I gave it some good hard brake applications and not a drop of leakage as well as a nice solid pedal. Bled all new Motul RBF 600 fluid into it. I did a lot of research on o ring composition for fluids and EPDM should work good for a polyglycol based brake fluid. Neoprene (for the one quad ring on the valve) is also ok for this. I have plenty of extra o rings and I plan on leaving them in a cap of brake fluid for a bit to see how they fare just to be on the safest side.
As I understand, the EPDM material does not degrade in brake fluid like neoprene, viton, or "standard" rubber would break down.
A sample of o-rings soaking in brake fluid is a good start to test their strength and durability. However, putting them through dynamic tests, such as fluid pressure and fluid flow, may provide better results.
Unfortunately, I don’t really have a way to dynamically stress test the system under controlled conditions. TBH, my stress test for the system will be this weekend, at the track! I plan on driving it to work to get some more miles and shakedown out of it, then the real beating will happen at the track.
FWIW, the composition of the o ring will grant a greater longevity and reliability of the system. How much so, I have no controllable way of measuring. Currently, I plan on leaving some of those O rings in brake fluid for a few days and then poking, prodding, yanking, twisting, etc on them. The good thing is that all but two o rings are static seals. So we don’t have to worry about leakage past seals and what not during dynamic events. I can post the listing of seals used, however I would like to do so after the track event. For liability reasons, I want to personally make sure it’s good before someone goes to perform this action and something happens. I’m very confident in my work however that I’ll be able to run all sessions with zero issues.
I understand completely about dynamic tests. I don't think many of us have a test bench to cycle widget "x" under specific conditions. I do wish you the best of luck at the track this weekend (not exclusively related to the ABS repair)! Additionally, I applaud your conservative approach to advertise a list of parts for the repair. Please update us on the list of parts after your tests are finished.
Have fun at the track! Perhaps you could share that experience in a different topic?
mine is leaking too. About a quarter cup of brake fluid every week or two.
Debating trying to buy a used one and hope it does not leak or try a rebuild.
How many hours of work would you estimate to do a functional rebuild itself, without worrying about beauty?
( presume shop numbers for pulling it and replacing it are valid...)
It took a maybe 2 hours to pull it, rebuild and reinstall it. Bleed the brakes maybe another hour if you have a pressure bleeder. 100 street miles, 3 twenty minute track sessions, and 1 time attack session and this is how the pump looks after the rebuild.
Still have a few o rings soaking in brake fluid. Been about a week now. I’ll let em sit for a bit more before I pull em out and play with them.
Did I miss the final approved list of O ring sizes and material, and hopefully part number? I saw some up there that looked like interim part candidates.
I would like to follow up with you about the long-term test of the ABS Hyd Unit (ABS Pump) and those new o-rings. Is your Hyd Unit sealed up and performing well? How are your sample o-rings doing after soaking in brake fluid for several months? Are you confident of these results to share your parts list?
I left a set of the O rings I used in the ABS pump rebuild in a cap full of RBF600 and they survived! I took em out, dried em off, and inspected them for drying, cracking, swelling, and weakness with no defects noted.
Excellent! Thank you for sharing your long-term research and final parts list. I presume that the old/worn parts in the last photo are on the left while the new parts are on the right?
Excellent! Thank you for sharing your long-term research and final parts list. I presume that the old/worn parts in the last photo are on the left while the new parts are on the right?
You ARE the man!
Cheers,
George
You would be correct. It’s a recycled photo from earlier in the thread but still relevant. Old rings on the left and new on the right. If those O rings lived through a 4 month soak, I’m confident they’ll be a good fit.
thanks Matt! I ordered a set. My unit is leaking also. With the engine pull, I might as well add another thing to the list. Obviously I don't need 10 of each so if anyone wants to split the cost, PM me.
I just ordered a set of O-rings. I think one of the o-rings (the -116) are out of stock, don't know if they will hold the order until they are in stock or not.
Anyhow, I went ahead and got 10 of each (they are CHEAP) and got 20 of the -009 o-rings since you need more of those, that way I will have enough to do a few pumps.
My total was $15.60 with $9.50 shipping. Remember, I got 20 of the -009 o-rings.
Buddy of mine has a spare ABS pump, I think I'll have to go through that one to try this all out!
Matt, awesome work man! It’s been a long time coming and the forum owes you a debt of gratitude!
I wonder if you might be able to use your expertise to help me out? I have a pretty clean looking ABS pump with low miles - only 51k, as I’ve got a low mileage car. My pump never leaked, but it did lock up my front wheels after pressing the brakes; meaning it would hold pressure in the front wheels until I either opened the bleed screw in the caliper or relieved pressure at the pump itself by loosening a line.
Do you think replacing the o-rings and rebuilding the pump would have any benefit? I removed the pump and installed a Alex Rodriguez kit, but I miss having ABS. Not having it makes me a bit nervous while driving her.
Matt, awesome work man! It’s been a long time coming and the forum owes you a debt of gratitude!
I wonder if you might be able to use your expertise to help me out? I have a pretty clean looking ABS pump with low miles - only 51k, as I’ve got a low mileage car. My pump never leaked, but it did lock up my front wheels after pressing the brakes; meaning it would hold pressure in the front wheels until I either opened the bleed screw in the caliper or relieved pressure at the pump itself by loosening a line.
Do you think replacing the o-rings and rebuilding the pump would have any benefit? I removed the pump and installed a Alex Rodriguez kit, but I miss having ABS. Not having it makes me a bit nervous while driving her.
Thanks!
Nick
Nick,
Unfortunately, I don’t think repacking the ABS pump will fix your pump. There are three solenoids that control the fluid flow to the calipers: one for each front caliper and one for both rear calipers. I feel like if the valve is stuck in the closed position, it might cause your symptoms. I haven’t tried to do component maintenance at that level so I’m not sure if you can replace just that solenoid without chopping it out and splicing a new one in. Does it lock up both brakes in the front? Or just one?
I'm currently working with Leeroy_25 on testing his ABS Hyd Unit. I created a test circuit schematic for testing the ABS Solenoids. Perhaps that may help you identify a bad solenoid and valve? Frankly, I could use some additional data from other units too. Feel free to check it out here: Post #68 - ABS Solenoid Test Schematic. Additionally, I ask for more data on the diode in the Hyd Unit. That thread talks about measuring it.
I would appreciate any feedback on the diode & solenoid tests. Thus far, Leeroy was unable to hear his solenoids click when voltage is applied.
I'm currently working with Leeroy_25 on testing his ABS Hyd Unit. I created a test circuit schematic for testing the ABS Solenoids. Perhaps that may help you identify a bad solenoid and valve? Frankly, I could use some additional data from other units too. Feel free to check it out here: Post #68 - ABS Solenoid Test Schematic. Additionally, I ask for more data on the diode in the Hyd Unit. That thread talks about measuring it.
I would appreciate any feedback on the diode & solenoid tests. Thus far, Leeroy was unable to hear his solenoids click when voltage is applied.
Cheers,
George
I don’t know that you will hear any of the solenoids click. They’re strange. So when I pulled mine apart, you can pull the bottom out of those cylinders and break it down to like a valve, a magnetic coil, and the top and bottom portion. I don’t know how the valve physically “works”, but I’m not so sure you’ll hear a click either.
Me Too -- labor?
I got a spare one waiting to get stripped 
