Looking for the people who are ok with rebuilding calipers. I expect a lot of people will tell me to just buy new calipers, but I am broke and need to only do what is absolutely necessary.

My question is around the pistons for my front calipers. They are the standard dual piston. My car is an XS, so even though it is a sport model, the all wheel drive means that I didn't get the big brakes. The insides are very rusty but the outside looks great on all but 1 of the 4 pistons. One seal had a tear that allowed dirt and moisture in and that piston has a lot of pitting.

I am thinking that I should go ahead and order 4 new pistons but just curious on the thoughts of the inner rust if I did reuse them with new seals.

Also wondering if maybe taping off new pistons and spray painting the insides might be a good idea before installing to help prevent future rust?

Also included a picture of the pitted piston.

 

Ordered new pistons for front, new seals, slide pin boots, and copper washers for all. I can tell the price of cooper is up when one washer is $1. Sheesh.

Plan is to clean calipers up while waiting on parts. Any suggestions? Current thinking is to stuff paper towels where pistons go while using the wire wheel and brushes. I wish I had a proper parts cleaner bin, but I don't. Then spray out with brake cleaner and immediately apply fresh brake fluid to insides to prevent any oxidation. Thoughts?

 

What about cleaning out the caliper bores? There's a special honing tool for this.

 

Interesting. I have an old brake honing tool from when I used to have a 65 mustang with drum brakes. But I seem to recall doing that because the inner walls of the brake cylinder had some corrosion on them. I will be sure to check the calipers really good, but my initial feeling was that they look very clean. Even the one that had the corroded piston in it seemed to wipe out to a shiny smooth surface. But, I suppose that doesn't mean that there could be some defects that I can't really see or feel.

I know the diameter of these is probably bigger than the brake cylinders I remember. I will do some research, but just wondering if there are different size tools and if the one I have will work or if I will need a different one.

Assuming I have one or get one, I assume I would just need to do a very quick "spin cycle" to remove any potential burrs or imperfections?

 

Good questions. I have no experience doing this practically on a modern (or semi modern) car. Last time I used a honing tool was in HS to rebuild some wheel cylinders on a go cart in the previous century. Come to think of it, last car to need calipers was my 4th gen camaro, which got some reman junk installed. As an outdoor car (never garaged), those calipers lasted maybe 5 years before rotting again.

The way I drive and brake, pads should easily last me 70-100K mi. These brakes (floating caliper) do require some periodic maintenance to keep from seizing up. Cleaning and slide lubrication. Change fluid at least every 3 years, etc.

 

Are you going to paint the calipers and brackets?

 

If I had a way to really clean them up good, I would probably paint them. As it is, I am just hoping to get them so that I don't have to do much for the rest of the life of the car. Maybe another 90k if I am lucky. I know now to really keep an eye on the dust boots. I know they were good 3 years ago, but 2 of them somehow got tears in them since then. My neighbor has started letting me use his garage, which has a lift in it, so I am hoping I will be doing my own oil changes and tire rotations and I can keep a better eye on things.

 

So the pitting does appear to be significant... if there is noticeable thinning of the metal it may become an issue. I have seen tons of pistons pitted on the inside since that is the more exposed area. If it isn't significantly thinning and if it is smooth on the outer side i.e. the part that slides in the caliper that's the main part, it just needs to be able to handle 5-10psi so when you hit the pedal the pistons move.

If you wish to use a rust converter go for it, but realistically paint is almost as good. Anything that'll drop the amount of oxygen and water that can hit the piston will help.

 

I went ahead and ordered new pistons for the front brakes. At $24 for all 4, it seemed like a no brainer. Just crossing my fingers that they are truly the same size. I will be checking with my caliper when they come in. LOL....I will be checking my caliper pistons with my caliper. I think I will hit the insides with some paint though. This car lives outside and so I think that is at least partly responsible for the accelerated rust. I also have plans now to hit the underside with some spray-on rust converter and then some spray-on undercoating....something I should have done years ago it seems.

 

I ran into a new problem. I had the dealer replace one of my rear calipers a few years ago and now they are different. One has the seal that fits inside a groove inside the caliper and has a metal retaining clip. The other caliper has a seal that feel like it has a hard piece built into it and it sort of presses into place. I can get some pictures posted tomorrow.

I ordered the Carlson 15287, which appears to be the press in kind. But I need one of the other types now and I am not sure which one is the type I need. What's weird is that the one listed for Brembo brakes appear to have the retaining clip, but this is not a Brembo caliper.

 

I use RockAuto a lot, they have good prices and a lot of parts. Per their DB, the style of piston that would fit a 2009 G37 rear brakes non-sport with the clip would be a Carlson 7909, but you could also try a CENTRIC 14645018.

Give the Rock Auto search a try, check their parts and pictures, and pick what seems appropriate.

Good luck!


Rick

 

I bought everything through RockAuto. The problem is not the pistons as I am re-using the ones for the rear. The issue is the seals. I looked at all the pictures, which is why I mentioned that the pictures for the Brembo seals is what has the metal retainer ring that one of the calipers has.

 

How much are calipers? $70/ea or so for a reman? Might be a better solution than the hassle you're experiencing.

 

I agree that this has been a bit more of an ordeal than I had planned, but mainly just because I underestimated the PITA it would be to clean these things up on a bench grinder. I would never attempt this again without using a blast cabinet.

But buy a new caliper because I need to find the correct seal? I hope I don't have to do that. I did not expect the dealer to put a new caliper on my car that took a different type of seal than the caliper on the other wheel. I find it strange that RockAuto does not seem to think there could be two different seals for a non-Brembo rear caliper.

Her are pics of the calipers in question. Hard to get a good picture that makes it easy to see what I am talking about. But hopefully you can see the difference.

caliper 1



caliper 2

 

They do look difference. Look at the designs near the outside of the bores. That's why dealers replace these rather than rebuild. Nissan can change suppliers so calipers are slightly different but still perform similarly. All dealer cares about is that part # specified in computer is what goes on the car. So long as the pads/mounting holes fit, all is good.