Piston Boot/Seal DIY

[GreatWhiteNorth]

Hi,

I tried doing a search for a DIY write-up on replacing caliper piston boots and seals. Nothing applicable came up.

Can anyone direct me to the proper link?

Thanks.

 

[DanO]

Originally posted by GreatWhiteNorth:
Hi,

I tried doing a search for a DIY write-up on replacing caliper piston boots and seals. Nothing applicable came up.

Can anyone direct me to the proper link?

Thanks.

Front or rear?

I've done the fronts. Pictures and manual pages here: www.danoland.com/nsxgarage/brakes/overhaul/overhaul.htm

I have not gotten around to posting a write up on this procedure. Getting the boots back on the pistons is a real challenge. Tom S (former local NSXER here in Ann Arbor) made a pretty cool little funnel that helps with this procedure. I think there’s a picture of his little device somewhere on the net (I can’t remember where). If you don’t want to make this modified funnel device then a second pair of hands can work too. I think Mr. HomeDepotNSX’s helped replace mine. With a little practice it can be done solo too—I’ve done a few that way.

Anyway, I don’t think there’s much out there on the web that outlines this procedure. There is a procedure listed in the service manual. Why don’t you take a look at the procedure and post any questions you have and we’ll try our best to answer them!

Good luck,

DanO

 

[GreatWhiteNorth]

DanO,

Thanks for the link.

My immediate requirement is for the front caliper.

A few questions regarding the procedure;

1. What is the best way to disconnect the bango bolt without losing too much fluid. Someone suggested to pinch-off the brake hose with a visegrip. I'm afraid of damaging the hose using this method. Is there a safer way?

2. Do the seals and/or boots need to be installed in a particular orientation? I've not physically seen the parts other than the photos you provided and it is not clear to me from seeing the photos. The seals appear to be simple o-rings, thus I presume these don't require any special attention however I suspect the boots may be a different story.

3. Is there a preference on the brand of silicone grease I should be using? Any special requirements (eg, temp rating, viscosity, etc ) I should be looking for in selecting an appropriate one to use.

4. I noticed from your photos, the piston has a groove for the boot but I did'nt notice one for the o-ring seal. After the caliper has been cleaned and re-lubed with brake fluid ( as suggested in the OEM manual ), do you simply insert the seal into the piston hole and slide the piston afterwards???

5. Do the bango sealing washers need to be replaced or can I reuse them if they appear to be in still good condition?

6. Once I remove the pistons, what physical defects should I be inspecting to determine if the piston itself requires replacement. I have noticed mine have a lot of "baked-on" black residue built up in the inside hollow section. I suspect this is may a buildup of burnt fluid. What can I use to clean this out?

Thanks in advance.

GWN

 

[DanO]

Good questions!

1. Do not use a vice grip on the brake line! You can remove the line at the fender end and plug the line with the rubber bleed cap. Removing the line this way requires an XXmm flare wrench (I can’t remember the exact mm but I can check later on, I can also send you a wrench if you need one). If you remove the line at the banjo then you’ll need to plug it some way—probably a XXmm bolt through the banjo would work just fine (again, I don’t know the exact mm but I can put my calipers on a banjo bolt later on this evening).

2. The seals and boots do not need to be installed in any particular orientation. Obviously, each caliper has two different size pistons and corresponding seals/boots. The seals are flattened o-rings.

3. I’m not 100% sure. I’ve always used a small amount of the silicone grease sold in my local auto parts store in the brake section, I believe the brand is Permatex (http://www.permatex.com/products/prodidx.asp?automotive=yes&f_call=get_item&item_no=20355). Now that I think about it, it’s probably not the correct stuff to use for this particular application. Hopefully someone here will be able to comment about the best silicon to use for brake work.

4. If my memory serves me correctly: first the seal goes in, then the boot seal (which is part of the boot) and then the piston. The hard part is fitting the piston in through the boot while keeping the seals in place—this is where an extra set of hands is helpful.

5. The banjo washers are known as “crush” washers are sacrificial and must be replaced. These crush washers are made of a soft metal that forms a perfect seal between two harder mating surfaces by allowing any imperfections and/or debris to become part of the seal. These washers can not be re-crushed. The washers are inexpensive and I usually order 10 at a time.

6. You should inspect the piston for any obvious scoring or imperfections. Most likely they’ll be in perfect condition. I’d use regular ‘ole brake cleaner on the inside of the pistons. If you can’t get all the gunk out then I wouldn’t worry about it.


One safety note: when blowing the pistons out with an air compressor [edit: the method to remove the pistons from the caliper], please turn down the regulator and use a wooden block to stop the pistons. Trust me, with just a little air, those pistons will shoot out of the caliper like a bullet out of a gun. Make sure your hand is not in the way and make sure they’re not pointed at anything that you care about.

Good luck and please let us know if you have any more questions,

DanO



[This message has been edited by DanO (edited 04 November 2002).]

 

[Gary W]

Originally posted by DanO:
Good questions!

1. Do not use a vice grip on the brake line! You can remove the line at the fender end and plug the line with the rubber bleed cap. Removing the line this way requires an XXmm flare wrench (I can’t remember the exact mm but I can check later on, I can also send you a wrench if you need one). If you remove the line at the banjo then you’ll need to plug it some way—probably a XXmm bolt through the banjo would work just fine (again, I don’t know the exact mm but I can put my calipers on a banjo bolt later on this evening).

The correct flair wrench is a 10 mm.

The best way to keep the brake fluid from leaking out is to put a piece of Saran plastic wrap (like the stuff you wrap your sandwich in) over the brake reservoir and secure the lid on top of that. That creates a vacuum, like when you put your finger over the top of a straw and removed it from the soda pop and the soda is still in the straw until you removed your finger. Not rocket science but it works great.

Gary

[This message has been edited by Gary W (edited 04 November 2002).]

 

[Larry Bastanza]

Gary,

Interesting tip. Do you cut a hole in the saran wrap to accomodate the float for the brake fluid level?? Or do you just wrap the float and seal the cap?? Or do you leave the original cap off and secure the saran wrap with a rubber band?

Thanks,
LarryB

 

[Gary W]

Just open the lid and place the Saran wrap on top and close the lid. That's it.

Gary

Originally posted by Larry Bastanza:
Gary,

Interesting tip. Do you cut a hole in the saran wrap to accomodate the float for the brake fluid level?? Or do you just wrap the float and seal the cap?? Or do you leave the original cap off and secure the saran wrap with a rubber band?

Thanks,
LarryB

 

[Larry Bastanza]

Cool,

Thanks,
LarryB