Clutch master cylinder rebuild?

[Cal]

Ok the master is slowly weep leaking into the car. I remember fixing this years ago and I thought they had a rebuild kit from Acura. Dealer says no such kit exists today and replacement masters vary from $240 (shipped from dealer) to $140 Dali racing. They seem to be on backorder so I don't really know how soon I can even get the entire assembly. Don't know if SOS or Dali even has one in stock (no one around holiday weekend). The local restoration buffs are telling me I can rebuild this myself. Anyone gone this route? Seems possible. First repair was about 50k, got 154k today. Seems like the hardest part was getting that cotter pin back in. Took me over an hour and when it finally worked it felt like it was just luck that things lined up. Hard to describe if you haven't done it yourself.

Cal

 

[Larry Bastanza]

Dealer list for the M/C is $178.85. They are readily available, I just checked, no backorder. Call a discount dealer like Tim Poloniak, for a discount price.

HTH,
LarryB

 

[ftuhy]

WAGNER Part # CM140593 {#F140593}, $85.79 from RockAuto ( www.rockauto.com ) appears to be the OEM part in a different box. I couldn't find a lump, bump casting mark, etc that didn't match the OEM unit in my '96.

 

[nsxnut]

I have a few spare "used" working master cylinders. PM me if you want one. $40.
[email protected]

Located in San Jose Ca

Later,
Don

 

[Cal]

Thank you all for the quick responses. Sounds like my local Acura parts guy is off. I'm intrigued with the idea of rebuilding it myself. Sounds like no one has actually done this yet. Long term we (first geners) will be like the vintage 64 corvette guys with limited options. I'm going to take mine apart and see just how hard this would be. A friend suggested any local competent brake shop should be able to do this. Will update on my final solution.

Thanks again!

 

[davidf]

They can be a PITA to get out/in. You sure are trustworthy on the rebuild. Your braver than me.

 

[chussey]

I'm in the same boat as you, would prefer to repair/rebuild my parts rather than replace. If nothing else it gives me the feeling of being more connected with the mechanical workings of my car. Looking forward to learning about your rebuild adventure. Post pics!

 

[ftuhy]

I saved the original one and have the tools (cylinder hone) to rebuild it. I need to find a rebuild kit, then rebuild it for when this one goes.

The reliability on them is not great. My '84 Corvette is on the factory clutch and brake master with 102,000 miles. I know a number of NSX owners with the same experience -- that their other sports cars of similar or older age are on the factory clutch master but have had to replace the unit on the NSX. Curious.......

 

[davidf]

I'm in the same boat as you, would prefer to repair/rebuild my parts rather than replace. If nothing else it gives me the feeling of being more connected with the mechanical workings of my car. Looking forward to learning about your rebuild adventure. Post pics!

Just removing/reinstalling/bleeding, you will feel completely connected. I promise.:tongue:

 

[Cal]

They can be a PITA to get out/in. You sure are trustworthy on the rebuild. Your braver than me.

Ahhh. So someone has done this before! I have rebuilt the calipers and getting things apart was not a big deal. The compressed air part is essential to getting the pistons out. Not sure how the master comes apart. I just assumed that the rod simply pulls out or unscrews. Again vintage restoration guys do this all of the time. I figure if corvette guys can figure it out surely an NSX owner can do it. The question is ... can this NSX guy pull it off. Well at least I have a source for backup masters if it doesn't work. I don't know if time/parts/PITA issues might make it a no brainer to just do a complete replace. If a NSX Jedi master like Larry doesn't mess with this... perhaps it is not a good idea.

Not sure what you meant about the "trustworthy on the rebuild" part. (Not sarcasm just curious). Anyone working on their brakes is going to have to trust they are doing it right. Seals either work or they don't and fast leaks should be pretty easy to tell. Slow will have me back to square one and just replacing everything. Seems like I remember bleeding the system took FOREVER. At least compared to bleeding the brakes. Much longer lines.

 

[chussey]

Just removing/reinstalling/bleeding, you will feel completely connected. I promise.:tongue:

If doing $25,000+ worth of body repair when I first purchased the car hasn't yet left me feeling connected, I'm not sure if anything will. :wink:

 

[htmachine]

Guys,
It is really very easy. I have restored English cars for 40 years and their rebuild kits are just seals. You have to be very careful not to nick them when installing. But the NSX kit is a complete Piston assembly. You remove the master, pull off the rubber boot remove a internal snap ring, use compressed air to pop out the old piston and lube and install the new. Reinstall the snap ring, boot and put back in the car. Worst part of the job is lying on your back under the dash to unbolt and remove the pin through the peddle connection. You should inspect the bore of the cylinder to make sure there are no scratches but I have never had that issue ever. My Nsx had 232,000 miles on it and the master worked fine just replaced clutch and thought I should replace everything. I would also replace the slave and slave hose also if you are doing the Master just to be safe. The slave moves when ever the master does. Our cars are getting older and the rubber hoses won't last forever. Also I had to adjust the length of the pushrod to bring the peddle play into spec, but you can't do that until you bleed the system.

 

[Cal]

Wow, thanks, I did get the snap ring out but it looks like it there is an internal ridge that would stop it from sliding out. I'll try the compressed air today and post pics.

On a separate note...Do you know Keith Ansel? He known nation wide as a big time antique British car mechanic. He has a shop locally (Battle Ground WA) and was the initial prompts that I could probably repair rather than replace.

- - - Updated - - -

Finally was able to get it apart, compressed air did the trick. Not sure how to disassemble any further. NSX prime doesn't like the jpeg files I took on the iPhone. Not sure how to get them on here. Perhaps if someone else knows how, I can e-mail them to you. I can see two seals but not sure how to get them off. Much easier to explain if you could see it. Might run it by my local British car buy to see if I'm missing how to get the seals off. I doubt if you just slip them over the internal cylinders, they seem to big.

Well you do just slip the seals off. Will post pics shortly.

 

[htmachine]

Sorry, don't know Keith. Being on the right coast I wouldn't have bumped into him at a show. Its just a hobby for me. I guess I'm just a masochist. I met my future wife after I restored a Lotus Europa and she figured if I had that much patience then I could put up with her. The rebuild kit I purchased was a Dorman CMK116440 Clutch Master Cylinder Kit, $21.05 from amazon. Everything was already assembled on a new piston shaft w/ the springs and everything. It is a lot more difficult to replace the seals. Getting them off is easy, just cut them. But to put them on I use a very sharp dental pick but not everyone has one. You have to be very careful not to tear them and put them on facing the correct way. Use Girling rubber lubricant. Or just get the Dorman kit.

 

[Cal]

Here are the pics of the disassemble piston assembly.