Brakes: Restored! Not just rebuilt...

[conedodger]

I am pretty stoked! I have a friend who does all of my Porsche brake work. He is pretty well known amongst the Porsche and Ferrari guys. I have been getting a lot of pressure from my local Z friends to take my Z out on the track now that she is running but I like to go through the brakes first before I drive anything on the track or autocross... Shame to bend her up after all this work right...

Anyway, back to Eric. I asked him if he would be interested in taking a look at restoring my Z brakes. Eric doesn't just rebuild. Pretty much anyone can do that. That means to simply make them serviceable. Eric RESTORES them. They look just as the factory intended them to look the first day you saw the car if you had been lucky enough to be an original owner.

Eric finished my brakes today sometime and he posted some pics on Facebook. I asked him to come here and tell some secrets about brakes...

Now before someone tells me that they put Toyota 4X4 brakes on their car I should tell you that I strongly believe that the factory engineers knew what they were doing. a good serviced set of brakes especially with modern pad and shoe compound will be all most of us ever need. Really.

Here are a couple pics of the car these are going on, hopefully Eric will chime in and tell us about restoring brakes...

[Zedyone_kenobi]

Glad to hear it, and I have to agree. I completely redid my brake system and the brakes kick in HARD. I put a good modern pad on them and I have yet to have any need for more stopping power than my 150 HP engine can make a need for. I guess to some more is better, but for a street driven car, the stock brakes when working well, are darn good.

[conedodger]

I would go that one better... When the original brakes were designed by the engineers at Nissan, they were better than they needed to be. Eric was impressed with the size of the brake and pad. The 240Z weighs a bit more than my Porsche 914 but the brakes are larger by a a greater proportion. The Porterfield R4S pad that I intend to use both front and rear to maintain the balance the original engineers intended should be more than enough for 200+ HP on the track or autocross. Wheel to wheel racing is different for sure. You use your brakes to negotiate traffic. On track days, you use your brakes to set the suspension for the turn. Well serviced brakes shouldn't get too hot doing that.

Bigger isn't always the answer. Heat is the real enemy. Getting it out of the caliper and rotor are key.

[Eric_Shea]

Thanks Rob,

I'm more than happy to show the process. I'm fairly picky about vintage calipers and how they should be treated, especially with some 40 years on the clock. I'll show what I think is right... it's not really that much beyond a standard rebuild once your in there.

I'm fairly new to the site so I'm not sure if image tags will work etc. so bare with me as I figure it out.

Looks like image tags aren't the answer. I'll include some pictures of the start. I think I'll make them a tad smaller so they don't take up so much room on the server. This will be a little clunky as I'll enter a few pictures at a time and discuss.

Here's what we started with. The first thing to do is prep the caliper for complete disassembly. The pins come out and the dust boots come off. Once that is done we mount them in the vise and install a 10x1 nipple valve so the pump can do it's trick:

Edited June 5, 2011 by Eric_Shea

[Eric_Shea]

Next we use a set of piston clamps to hold the outer piston in place while we use fluid to blow out the inner piston. There's a couple things at play here and I'll describe the tools and the purpose behind all of this.

First off, let's go back to the 10x1 nipple valve and the "fluid" comment. I'm sure that most people reading along, who have rebuild calipers at one time or another have used the "pressurized air" method. You simply clamp off a piston and blow pressurized air into the caliper and "pop" out comes the piston. This will work on most calipers that have been working on the car. If the caliper or the car has sat for any length of time, the area above the bore seal will begin to contaminate with what I like to call "caliper shellac". This is a combination of rust and fluid that has passed the seal. This is what causes pistons to bind in the bore. Nearly 50% of the calipers we service will not come apart with air. Hence, a fluid is needed to push these pistons out. Fluid is safer as well. A piston letting go with compressed air has the velocity of a bullet coming out of a gun. This can damage your pistons and your caliper. With fluid they just "plop" out. Bottom line, fluids do not compress and they will do the work that air cannot in the case of a stubborn piston.

Tools: I'll show what we're using and, in the case where there's a garage bench substitute, I'll pass that info and method along. In this post, the caliper clamp is nice but not always a necessity. You can get by with a small c-clamp holding one or both edges of the opposing piston. You just have to make sure they're not in the way of the other piston you're attempting to remove.

Inner Piston: On most calipers I like to remove this piston first as it allows better clamping access to cover that bore. You'll see how this progresses.

So here we'll hold the outer piston in place and use fluid to pump out the inner piston. In the 3rd picture you can see it coming out:

[Eric_Shea]

Once the inner piston is out we need to seal up that bore and pump out the outer piston. To do that we use a fairly large rubber stopper and a steel plate. I use the vise to clamp the bottom of the plate with the caliper ears and a few c-clamps on the top to secure the rubber plug in the bore. If you don't have a large enough rubber plug, a large rubber washer and the steel plate will also work. For many of these pieces www.mcmaster.com is invaluable.

Here are some shots of the cover in place in the piston removal:

[Eric_Shea]

Next it's time to bust loose the 14mm M9 fasteners. These were in pretty tight so I used a longer breaker bar to get them started and then wrenched them out.

Once they're apart we simply pick all of the seals out and remove the bore plug. These are now ready for plating:

[Eric_Shea]

A word about plating (and yeah, I'm pretty anal about this stuff):

We get this all the time; why not just paint the calipers:

1. Paint only protects the outside of the caliper... not very well and only temporarily.

2. Paint comes off with odd things like... brake fluid and brake cleaner.

3. Paint can actually encapsulate the caliper trapping in heat.

4. Zinc is the factory finish and has superior "sacrificial" corrosion protection.

5. Zinc re-plates the bore, which it probably needs it by now.

Rebuilders that paint calipers do so because zinc is expensive. They can easily slap on a coat of paint on "in-house" and it speeds up the process. They can even call it cool things like "Ceramic" or "Polymer" etc. If you want your calipers done right they will need to be zinc coated like the day they left the ATE factory.

So as you're reading along, I take it you've come to understand that I'm not a big fan of painting your calipers. True. In fact, I think it's one of the goofiest trends we've seen since Porsche put the first set of "Big Reds" on a car and others spray painted their way to glory. That said... to each his or her own.

Plating at this stage of the game will probably take about 1 week out of your schedule and, if you look around you can probably get the whole shooting match done for around $50-60.00 bucks. This will ensure that your "vital" brake calipers will give you another 40 years of service.

Off soapbox...

Here's a shot off the units returned from plating:

Oh Wait... Before that, I forgot to mention that we needed all new pistons for these beasts. I've yet to do enough Z caliper to know if this is common or not (Porsche S-Calipers are the worst for this) but these were trashed. The new units look great and are in these pics as well.

[Eric_Shea]

Let's get this party started.

Next we start the fun process of putting it all back together. This starts with seals and dust boots.

For the seals, I like to just walk them around in the groove and push the final bit into place. An angled dental pick can help if it gets a little twisted. Just run it through the groove and the seal will usually sort itself out.

For the dust boots, I like to install these before you put the pistons in. This may seem obvious but, I've had the question arise. I also go around and tug the edges and look at the seal to the piston from the bottom to make sure they're seated properly.

[Eric_Shea]

Big Derpy-Der Moment: I just realized that we didn't get any pictures of the pistons going in with the Arbor Press. I'll do my best do describer here but, it's pretty straightforward with these:

1. Get "Brake Caliper Assembly Lube". Other assembly lubes can swell your new seals and ruin your calipers. PEP Boys has it in single use tubes. We use the ATE assembly lube. I like to put a dab about the size of my thumbnail inside the bore and spread it around with an applicator brush. You can use a finger as well, just make sure it's evenly spread around the bore.

2. Simply press in the piston. I put both thumbs in and push down. It "should" slide paste the seal and drop right in. If not, a little persuasion from the arbor press is all that's needed. If you don't have a bench top press, a socket dropped into the piston cavity and a vise will suffice.

3. Once the pistons are in, make sure you wrap the wire dust boot clip over the top of the dust boot to secure it in place and keep water from getting in. Do this before you bolt them together and it's much easier.

Once the pistons are in place, install the rubber caliper 1/2 seals and drop your fasteners into the back 1/2 of the caliper. Hold the front half in one hand and pickup the back 1/2 in the other and drop the back 1/2 down onto the fronts with the new seals in place. I like to have a 3" extension loaded with a 14mm socket handy at this point as the process of screwing the caliper 1/2's together begins now:

[Walter Moore]

Impressive. Obviously the rebuilt calipers from the generic parts stores don't get this level of attention.

What does it cost to restore calipers to this level?

[conedodger]

Impressive. Obviously the rebuilt calipers from the generic parts stores don't get this level of attention.

What does it cost to restore calipers to this level?

That is a good question Eric. There are a bunch of guys here on ClassicZ that are original owners or own very low number cars. Between these guys and guys who want them done right (like me), I bet you will have some guys that will want you to do this for them... Hopefully they will not be as rusty and abused as the Sumitomo's I sent you!

You guys be sure to 'like' PMB Performance on Facebook if you want to see more of Eric's work including all these pictures in one place and original resolution.

Edited June 5, 2011 by conedodger