Going through my ABS pump
04-30-19, 03:21 AM
#1
Full Member
Thread Starter
Going through my ABS pump
While working on my 93, I noticed the ABS was beginning to weep around the solenoids, much like many of the others in 2019 im sure. The awesome thread done my Matt started me off ordering all of the recommended o-rings of various sizes and cuts to re-seal the pump, but while reading the thread, I noticed that the lower areas of the pump were not addressed. After tearing down the top side of my pump - solenoids, motor, pump elements - that has been gone over before, I took apart the lower 4 chambers, at the very least, to clean and flush old brake fluid out. My pump was very corroded externally from weeping, and then leaking for some time But also due to sitting outside for an unknown amount of time before I purchased the car.
Pic is huge, I don't want to kill people on mobile
https://imgur.com/nnUUFT0
This is the bore directly beside the pumping element of the ABS unit. It contains a spring, and retainer cap and not much else. The single port that is drilled into each bore (there are two, not connected) crosses vertically from the transfer pipes going to the distribution block ontop of the solenoids (where the brake lines connect) and through the pumping element bore. It seems to be more or less of a reservoir, or a way to reduce weight possibly? There is no free piston or active element like in the area I'll mention next. The area of mine on the FR/ FL circuit was full of a gross goo, most likely contaminated brake fluid that was not flushed. Removing the retainer cap was a pain in the ***, I had to compress the spring, and remove the thicc clip with a drift through a cross-drilled hole. The spring has a good amount of force and the retainer cap, while large in diameter, is somewhat shallow and can hang up and can suddenly pop out - wear a face shield if you are going to go to this extent of stripping your pump! These bores take the same seal as the top solenoid seal.
At the bottom area of the pump is what I am assuming is a pulsation damper for when the ABS is active to reduce pedal judder. There appeared to be a cross drilled hole from another are area of the pumping bore, to this one. Contained in the bore from inner to outer is a floating piston, a spring, a retainer cap with a low friction bushing to guide the floating piston, and then a retainer cap, clip and cover. I'm not settled that it is solely a pulsation damper, it may serve double duty to inhibit cavitation in another area of the pump while active. Removing the floating piston was a bit of a chore - im guessing it was stuck for not having been moved in a long time. I used soft jaw pliers but still marked the area that slides in the bushing. I dressed the area and smoothed it out before assembly. A purpose built pin vise would be a much better way of extracting stuck floating pistons. I'll probably make one for any future pumps I rebuild. The seal for the floating piston was not similar to any other in the pump - I took measurements and I'll be checking into what can be sourced. Luckily, my seals were in fantastic shape and I'll be reusing them for the time being.
Here is everything ready for assembly, minus new o-rings on the pumping elements.
https://imgur.com/qew9mWb
The solenoids come with a filter on the upper and lower sections, 6 in total. Mine were fairly dirty from time and most likely lack of maintenance. The lower filters can be removed if you are careful with a pair of tweezers. There is a conical spring facing towards the top of the solenoid, and a small check ball ontop of the spring. The filter has a plastic cage and a very delicate mesh - wash it with water and gently brush it with an acid brush, leave it to air dry, compressed air may tear the filter.
The top filter of the solenoids are staked on and can not be removed with out damaging the solenoid body, as far as I can see. If I come across a pump I don't mind taking apart further, ill investigate further. For mine, I used the same acid brush and very light solvent to brush what I could from the upper side of the top filter screen and let it air dry..
When assembling the top distribution block, the o-rings recommended to use for the outlet side, leading to the brake lines seemed to have a very small ID, and I was not confident using them as it was taking excessive force to seat the top block to the solenoids. I reused the stock o-rings which seemed to be in good shape, the ones that seal the small pin sized port at the top. The o-rings to seal the larger diameter ID and OD seemed to work well.
I'm still a few weeks away from a drive test, but so far the re-sealed ABS pump does not seem to be leaking in situ.
Pic is huge, I don't want to kill people on mobile
https://imgur.com/nnUUFT0
This is the bore directly beside the pumping element of the ABS unit. It contains a spring, and retainer cap and not much else. The single port that is drilled into each bore (there are two, not connected) crosses vertically from the transfer pipes going to the distribution block ontop of the solenoids (where the brake lines connect) and through the pumping element bore. It seems to be more or less of a reservoir, or a way to reduce weight possibly? There is no free piston or active element like in the area I'll mention next. The area of mine on the FR/ FL circuit was full of a gross goo, most likely contaminated brake fluid that was not flushed. Removing the retainer cap was a pain in the ***, I had to compress the spring, and remove the thicc clip with a drift through a cross-drilled hole. The spring has a good amount of force and the retainer cap, while large in diameter, is somewhat shallow and can hang up and can suddenly pop out - wear a face shield if you are going to go to this extent of stripping your pump! These bores take the same seal as the top solenoid seal.
At the bottom area of the pump is what I am assuming is a pulsation damper for when the ABS is active to reduce pedal judder. There appeared to be a cross drilled hole from another are area of the pumping bore, to this one. Contained in the bore from inner to outer is a floating piston, a spring, a retainer cap with a low friction bushing to guide the floating piston, and then a retainer cap, clip and cover. I'm not settled that it is solely a pulsation damper, it may serve double duty to inhibit cavitation in another area of the pump while active. Removing the floating piston was a bit of a chore - im guessing it was stuck for not having been moved in a long time. I used soft jaw pliers but still marked the area that slides in the bushing. I dressed the area and smoothed it out before assembly. A purpose built pin vise would be a much better way of extracting stuck floating pistons. I'll probably make one for any future pumps I rebuild. The seal for the floating piston was not similar to any other in the pump - I took measurements and I'll be checking into what can be sourced. Luckily, my seals were in fantastic shape and I'll be reusing them for the time being.
Here is everything ready for assembly, minus new o-rings on the pumping elements.
https://imgur.com/qew9mWb
The solenoids come with a filter on the upper and lower sections, 6 in total. Mine were fairly dirty from time and most likely lack of maintenance. The lower filters can be removed if you are careful with a pair of tweezers. There is a conical spring facing towards the top of the solenoid, and a small check ball ontop of the spring. The filter has a plastic cage and a very delicate mesh - wash it with water and gently brush it with an acid brush, leave it to air dry, compressed air may tear the filter.
The top filter of the solenoids are staked on and can not be removed with out damaging the solenoid body, as far as I can see. If I come across a pump I don't mind taking apart further, ill investigate further. For mine, I used the same acid brush and very light solvent to brush what I could from the upper side of the top filter screen and let it air dry..
When assembling the top distribution block, the o-rings recommended to use for the outlet side, leading to the brake lines seemed to have a very small ID, and I was not confident using them as it was taking excessive force to seat the top block to the solenoids. I reused the stock o-rings which seemed to be in good shape, the ones that seal the small pin sized port at the top. The o-rings to seal the larger diameter ID and OD seemed to work well.
I'm still a few weeks away from a drive test, but so far the re-sealed ABS pump does not seem to be leaking in situ.
04-30-19, 07:14 AM
#2
RX-7 Bad Ass
iTrader: (55)
Nice! I have a set of O-rings for the pump if ever the time comes.
Keep us posted with how it does when you hit the road!
Dale
Keep us posted with how it does when you hit the road!
Dale
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