ABS/ALB modulator rebuild write up

[CB72]

I'm currently rebuilding my modulator with Warren's kit.
The most difficult so far was to get the whole ABS unit out of the car.
Here are some pictures that show the corrosion.
I'm not sure if the bugs really get into the system but there was enough dirt in there to stop it from working correctly!
Many thanks to Warren.

 

[CB72]

I recently finished the installation of my ALB unit and went to the local Honda dealership to get it tested.
Bad news: the modulator that controls the front right wheel is leaking...
The good news is that in France( Europe?) the modulators can be purchased separately but...they cost almost 1000 Euros each!
I believe you can't get them in the USA?
For those of you that could be interested ( I doubt that) here are the PNs

 

[BobMc]

ABS rebuild

Help! I'm in the process of rebuilding the ABS modulator, and ran into a problem. Can't seem to be able to remove the valve/pistons from the assembly. Is there some procedure to get these buggers out? Thanks.

 

[CB72]

The way I did it was to insert a screwdriver against the springs and then use it as a lever.
The leverage point coming from another screwdriver set at the edge of the piston.
FYI, you will be wasting your time doing so if your modulators are leaking...
The test procedure is given in the NSX shop manual.
The modulator that suffers the most is the one that controls the front right wheel as it's typically the wheel that locks up first for LHD cars.

 

[NSXCessive]

Help! I'm in the process of rebuilding the ABS modulator, and ran into a problem. Can't seem to be able to remove the valve/pistons from the assembly. Is there some procedure to get these buggers out? Thanks. View attachment 101913

They should just push out they might a bit difficult but with the right amount of pressure they will come out the old seals are probably holding tight. See my pics starting from post #33

http://www.nsxprime.com/forum/showthread.php/164964-NSXCessives-91-Project-quot-Sliding-Knife-quot-Build/page2

 

[warrenw]

The o-rings in brake fluid create a great seal. it is just a matter of a slight pry to get them started. be firm but gentle at the same time.

 

[BobMc]

Thanks everyone, especially Warren who put this thread together. I'll try what you said.

 

[BobMc]

Got the abs unit back in, and it works great. Just some comments:
1. Many thanks to Warren and all that helped put this information together. This is a good example of how helpful this forum can be.
2. I had a local mechanic pull the unit out and reinstall it. It would have been too much challenge for me to do it all. They charged 4 hours labor which I thought was fair.
3. Getting the Allen head bolts off was easy with an air impact wrench.
4. Using air to push the valves out made it easy.
Hope these comments may help others who do this job.

 

[nis350]

Got the abs unit back in, and it works great. Just some comments:
1. Many thanks to Warren and all that helped put this information together. This is a good example of how helpful this forum can be.
2. I had a local mechanic pull the unit out and reinstall it. It would have been too much challenge for me to do it all. They charged 4 hours labor which I thought was fair.
3. Getting the Allen head bolts off was easy with an air impact wrench.
4. Using air to push the valves out made it easy.
Hope these comments may help others who do this job.

4 hours just to remove and reinstall the unit or it includes changing all the o-rings?

Did you also clean the solenoids?

Thx.

 

[BobMc]

4 hours just to remove and reinstall the unit or it includes changing all the o-rings?

Did you also clean the solenoids?

Thx.

The local mechanic removed and re installed the unit. I did the overhaul, including cleaning all the internals and new o rings.

 

[warrenw]

Glad things worked out. This little project has now saved about 30 - 1991 - 1992 ABS systems. Some have even been able to save later model units with my example writeup.
This is one of the few high maintenance parts on the car. With this write up, that takes it off the high maintenance list again for a while.
It is great to help keep the NSX on the road.
For those wondering, I still have o-ring kits left.
http://www3.telus.net/public/warshan/Cars/NSX/ABS/ACURA NSX ABS mod rebuld_v06.pdf

 

[nis350]

I might have missed the info somewhere. Do these o-rings have the same quality as the original ones?

Do you have any feedback from those who rebuilt the ABS awhile back. I am curious as to how they are holding up. Thanks...

Glad things worked out. This little project has now saved about 30 - 1991 - 1992 ABS systems. Some have even been able to save later model units with my example writeup.
This is one of the few high maintenance parts on the car. With this write up, that takes it off the high maintenance list again for a while.
It is great to help keep the NSX on the road.
For those wondering, I still have o-ring kits left.

 

[warrenw]

I might have missed the info somewhere. Do these o-rings have the same quality as the original ones?

Do you have any feedback from those who rebuilt the ABS awhile back. I am curious as to how they are holding up. Thanks...

I worked with Daemar to ensure that the the o-rings had the the abilty to work with brake fluid. Not all rubber is compatatble with brake fluid. Brake fluid will break down most rubbers, but not EPDM rubber (ethylene propylene diene monomer (M-class) rubber). All the o-rings are made of EPDM rubber.
http://en.wikipedia.org/wiki/EPDM_rubber
http://www.daemar.com/

The red rubber grease is a special grease for use with brake fluid. It is a vegetable base that will not affect brake fluid. The grease I selected is Castrol red rubber grease and is an industry standard for brake hydraulics. I had to import this stuff from the UK as it doesn't seem to be available in North America.
http://www.redrubbergrease.com/
http://www.bp.com/assets/bp_interne..._assets/downloads/t/Red_Rubber_Grease_TDS.pdf


The only issues I have heard, are from owners who's ABS systems are beyond repair. That was 1 individual.

Hope that helps.

 

[nis350]

Thanks for info. I've seen seals that came off 20 yrs old ABS modulators looking pretty good. Do you think the new o-rings would have similar durability?

I worked with Daemar to ensure that the the o-rings had the the abilty to work with brake fluid. Not all rubber is compatatble with brake fluid. Brake fluid will break down most rubbers, but not EPDM rubber (ethylene propylene diene monomer (M-class) rubber). All the o-rings are made of EPDM rubber.
http://en.wikipedia.org/wiki/EPDM_rubber
http://www.daemar.com/

The red rubber grease is a special grease for use with brake fluid. It is a vegetable base that will not affect brake fluid. The grease I selected is Castrol red rubber grease and is an industry standard for brake hydraulics. I had to import this stuff from the UK as it doesn't seem to be available in North America.
http://www.redrubbergrease.com/
http://www.bp.com/assets/bp_interne..._assets/downloads/t/Red_Rubber_Grease_TDS.pdf


The only issues I have heard, are from owners who's ABS systems are beyond repair. That was 1 individual.

Hope that helps.

 

[warrenw]

Thanks for info. I've seen seals that came off 20 yrs old ABS modulators looking pretty good. Do you think the new o-rings would have similar durability?

Timing belts come out of NSXs looking pretty good as well. but we change them because?
I found the best o-rings for the job. Highest quality available. If they last half as long as the originals, that will be longer and better than putting 20 year old o-rings back in after cleaning. I don't really know how long they will last, I lost my crystal ball. Sorry.

 

[nis350]

Got your o-rings installed a few days ago. I'd be very happy if I get another 10 yrs. Thx.

Timing belts come out of NSXs looking pretty good as well. but we change them because?
I found the best o-rings for the job. Highest quality available. If they last half as long as the originals, that will be longer and better than putting 20 year old o-rings back in after cleaning. I don't really know how long they will last, I lost my crystal ball. Sorry.

 

[Heartbeat]

I will post my experience with this kit. My problem was after 120 seconds of the pump running it would turn off and the yellow light would go on. I was concerned because the directions state that you must have one of the three symptoms listed-1.pump runs less than 30 seconds 2.pump runs all the time 3. pump never runs. Yet the other post regarding flushing the system for maintenance purposes described my situation.

The hardest part was removing the unit including disconnecting the six plugs. I could not reach the furthest back plug or the 4 bolts to remove the protective bar which interfered with the 6 brake lines. I disconnected the upper radiator hose and turn the unit 90 degrees clockwise so I could unplug the remaining plug and remove the bar. Then lifting the heavy unit out was possible. Rebuilding the unit was not that difficult except I forgot to put the 4 little springs in so I had to take it apart again. Only half the allen screws came out with the air impact wrench but no problem with 1/2" breaker bar. Prying out the 4 valves was easy once I realized they included the cylinder around them. All the new Orings fit perfectly. Since my 1992 has only 27,000 miles my contamination was only about half of Warrens but it certainly needed cleaning. I left off the protective bar since it is too hard to install and not really necessary as the spare tire is held OK.

The bleeding of each wheel was no fun. Since at the start I got solid brake fluid coming out but the pedal would still go the floor I was stumped. But later I opened the fitting more and I got solid streams and then finally air bubbles. So I wound up jacking the car up 12 times, 3 times for each wheel ( I am 73 years old). Then took the NSX for a test drive on gravel. The system seemed to work as the brake pedal pushed back. However, the pump would run for 120 seconds, stop and the yellow light would go on. So all the hard work may not have solved the problem and I reread all the posts. The next day I tried opening the bleeder screw for the accumulator and bubbly fluid came out. Closed it and added fluid and took it for a test drive with same negative results. Did the same procedure a second time and now it works perfect.

I want to thank Warren for the kit and instructions as the NSX Service Manual does not show this rebuild.

 

[warrenw]

Georg, good to hear, yet another NSX ABS system is back on the road.

FYI to everyone else. I have about 25 kits left. When they are gone, I won't be making any more. 91 and 92 ABS cars only.

 

[dablackgoku1234]

If I disconnect the 6 hardlines into the ABS, I would assume the car is not driveable. When the rebuild is done and it is time to reconnect the lines, do I need to flush the system to get the air out?

Also, is there any chance of the fluid in the brake cylinder mixing with the brake fluid in the ABS?

Edit: got my answer on the first question, need to flush the brakes after reinstall

 

[Heartbeat]

I don't think so but make sure to bleed the ABS also.

 

[neonshaun]

So, I've just finished disassembling my modulator. Thoughts so far:

Getting the thing out of the car took way more time than ripping it apart. To de-pressurize it, just switch one of the solenoids on and off until it doesn't push fluid anymore. As you do this, suck all of the fluid out of the reservoir.

As you disassemble everything, LOTS more brake fluid will squirt and spill out at various steps. There is currently a puddle of brake fluid under my car that I will have to clean up since it continued dripping out of the lines for a long time.

My modulator was FILLED with junk. Actually caked on the seals. There is also a lot of white chunky stuff, that looks like brake fluid gone bad. I found an entire IN TACT moth smashed under the plastic cover. Something about brake fluid attracts insects maybe?

Anyways, tomorrow I will try to reverse flow and unstick the solenoid that wasn't opening. So far so good, I guess.

So, I tried for 3-4 hours to free a stuck solenoid. I tried with pressure the right way, the reverse way... I clicked it so many times I thought I would burn it out. Never unstuck itself. Anyone know anyone who upgraded to the new ABS who might have some solenoids laying around?
Other than that, it all went back together smoothly. I believe if you removed the cruise control, you could do this whole process with the modulator still in the car.

 

[Luca from Italy]

Thanks to Warren for rebuilt kit shipped to Italy :smile:

 

[scott]

Rebuilt my ABS with warren's oring kit. The accumulator is holding pressure for several days now. So looking good. Thanks man!

 

[scammy]

I dont know if this is of any use to anyone but i recently upgraded to the new ABS system so have a complete system for a RHD off a 91 free to anyone who wants to pay for shipping.
It didnt make the noises much i just wanted to get rid of some weight and have a better system for the track

 

[CB72]

I would be interested in the solenoid valves:smile:
Do you believe you could get them out of the solenoid assy?
The reason I'm asking is to reduce the weight in order to ship by air as I'm located in France.
I recently acquired some parts in Australia and I still haven't received them because they were shipped by boat...
Thanks