Brake Rebuilding Project

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Tom Wilson
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Brake Rebuilding Project

Post by Tom Wilson »

<a ref="http://i107.photobucket.com/albums/m290 ... -Large.jpg" class="postlink"><img src="http://i107.photobucket.com/albums/m290 ... -Small.jpg" border="6"></a>

Over the weekend, I started working on my brakes. Given the length of time they have sat unused, they should probably be refurbished and resleeved. I will be replacing the brake lines and have the brake booster rebuilt. I have a small list of brake guys, but any suggestions are welcome. Someone in Southern California would be great, as I would like to meet them and learn about what they are doing.

<a ref="http://i107.photobucket.com/albums/m290 ... -Large.jpg" class="postlink"><img src="http://i107.photobucket.com/albums/m290 ... -Small.jpg" border="6"></a>

Question #1: Is there a way to get the brakes off without removing the steering arm? Am I missing something here? I would think you would not need to mess with that to fix the brakes, but the bolts hit the arm.

Question #2: Lots of penetrating oil and a breaker bar have loosened some of the bolts, but a couple still won’t budge. Tom Y has talked about using a torch to heat the bolt, but how hot? I have to be careful here because of the proximity to the brake lines.

More questions will definitely follow.
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tyang
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Post by tyang »

Hi Tom,

I believe your caliper frames need to come off so you can get the pistons off. If you're going to refurbish your brake system, you'd want these off to plate them in nickel along with the pistons. If you can't get a 1/2 inch socket with a breaker bar on the bolt, get a 6 point or a good 12 point box end wrench on the 17 or 19mm bolt head, apply more leverage with a pipe or another wrench hooked over the open end side. Make sure the wrench is perfectly seated on the bolt head before applying prodigious amounts of torque to save your bolt, and your knuckles!

If bolts are really seized, you have to use A LOT of heat. When Francois and I do it, the bolt gets dull red. I don't think you can get this kind of heat with a propane torch. I would try a propane torch first, however, to see if it gets hot enough to loosen the rust. Sometimes, as the bolt cools, a little bit of penetrating oil will get sucked in the crevases to help. Just don't spray it on when it's hot enough to ignite! Don't worry too much about setting brake fluid on fire. It'll burn, but not like gasoline. Have an assistant standing by as a spotter to make sure something isn't catching fire.

Good luck, and save those knuckles!

Tom
Last edited by tyang on Wed Mar 12, 2008 2:29 pm, edited 1 time in total.
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Tom Wilson
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Post by Tom Wilson »

Unless the one of the brake caliper bolts is shorter than the other or I am working on the wrong bolt, it appears that when I get it loose, it will hit the steering arm before it comes clear of the caliper.

As for the heat, I will start with a propane torch and see what happens. I am more concerned with melting the small brake line that goes from one side of the caliper to the other (equalizing line?) than setting the old grease on fire. That might help me with my cleaning!
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Post by tyang »

Hi Tom,

Is the top bolt to the caliper frame loose as well? The bottom bolt might not have to come out for the caliper to slide off the mounting flange.

The balance tube can come off if you're afraid of damaging it. It's got to come off anyway. Make sure you have the right flare nut wrenches. There's a mix if SAE and metric fittings on Ferrari brake tube fittings.

Tom
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Tom Wilson
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Post by Tom Wilson »

Just to make Rudy happy, I spent a good chunk of the weekend skinning my knuckles and bruising my ego removing the brakes on the GTE. Details can be found at http://ferrari250gte.com/blogs/toms-blog/

First, Tom Y was correct, the front bolt does not have to be removed; removing the rear bolt will allow the brakes to slide off with the front bolt loose, but in place.

Second, heat was not necessary to remove heat shield bolt I was having trouble with. Too embarrassing to describe on this site. My blog has lower standards though.

Now more questions:

What is going on with the bolts that hold on the rear discs? The disc can be removed, but the bolts hit a flange behind them and cannot be removed. The flange is held on by a group of inaccessible and very rusty bolts that do not look fun to remove. Any explanation on Ferrari's assembly techniques here and suggestions on how to proceed?

Both upper heat shields (front only) are cracked in the same place. Are they worth repairing or am I better off without them.

Is painting ok for the calipers or do they need to be powder coated? Should they be sent to the brake guy or should I only send the pistons?

Any suggestions on a Southern California brake guy?

Stay tuned for further questions...
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tyang
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Post by tyang »

Hi Tom,

Glad to hear you got the front brakes off.
Now more questions:

What is going on with the bolts that hold on the rear discs? The disc can be removed, but the bolts hit a flange behind them and cannot be removed. The flange is held on by a group of inaccessible and very rusty bolts that do not look fun to remove. Any explanation on Ferrari's assembly techniques here and suggestions on how to proceed?
You have to remove the rear hub. There's a flange with a seal that is attached to the brake caliper bracket. Get a new seal now, while you have everything apart. Also check the surface of the rear hub that slides along this seal surface. Make sure there are no imperfections that will make the new seal leak. Use some fine sand paper in a long strip to buff this surface smooth.
Both upper heat shields (front only) are cracked in the same place. Are they worth repairing or am I better off without them.
Are you taking the car to Pebble Beach?
Is painting ok for the calipers or do they need to be powder coated? Should they be sent to the brake guy or should I only send the pistons?
Nickel is the way to go. We strip and sandblast the calipers and frames before we send them out for resleeving. Can you move the pistons in their bores? Since you have compressed air, try blowing the pistons out to inspect the bores. Use a rubber tip on the compressed air, and plug up the other fitting. Go into the house, and warn your family that there will be a loud pop coming from the garage. Wrap the piston with a rag, and shoot some air inside. If the piston seems stuck in the bore, put the caliper half in a vice and try compressing the piston back in the bore. Spray lots of penetrating fluid and see if you can free up the piston, and then try the compressed air again.

Getting everything stripped will let you know what you'll need to do next, and save you some money having the brake rebuilder do it.

Good luck!

Tom Y.
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Jimmyr
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Post by Jimmyr »

Removing a stuck piston from its bore can be a difficult and sometimes dangerous task. Using compressed air through the bleeder can result in a damaging flying projectile. I made up a fitting using a old bleeder an a grease fitting which I screw into the bleeder and use my grease gun to slowly push the piston out. The increased pressure will extract even the most stuck pistons, and no explosion at the end. Jim
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tyang
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Post by tyang »

Jimmyr wrote:Removing a stuck piston from its bore can be a difficult and sometimes dangerous task. Using compressed air through the bleeder can result in a damaging flying projectile. I made up a fitting using a old bleeder an a grease fitting which I screw into the bleeder and use my grease gun to slowly push the piston out. The increased pressure will extract even the most stuck pistons, and no explosion at the end. Jim
The piston wrapped in a rag is key, but you're right. With the really stuck ones, we'll use grease, but what a mess!

Another thought for Tom is when using air (now if you dare), don't do it near painted surfaces (ie. car) as atomized brake fluid can land everywhere.

Tom
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Chris Coios

Post by Chris Coios »

If you are interested in originality, the plating for the caliper saddles, wheel cylinder castings, hardware and the bolts holding the wheel cylinders to the saddles is clear cadmium. The larger bolts holding the caliper saddle to the suspension are typically black oxide.
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Tom Wilson
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Post by Tom Wilson »

So is the piston supposed to blow clear out of the case? If so, I guess I need to try more pressure. I squeezed the piston in with a vice, then went as far as 80lbs of pressure and got the piston to move, but it stayed in the bore. How is it normally removed?

I was looking on Tom Y's suppliers page and noticed that Karps Brake Service is reasonably close to me. Has anybody used them?
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Rudy van Daalen Wetters
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Post by Rudy van Daalen Wetters »

Tom,

Careful on that air pressure. Sometimes what appears to be a stuck piston will pop out like a missile. Happens so fast you won't realize what
happened. Almost took my hand off on a seized piston in an ATE brake caliper from my Alfa GTV. I'm not as daring as I used to be.

Rudy van Daalen Wetters
1963 GTE s/n 4001
1966 330 GT s/n 8705
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Tom Wilson
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Post by Tom Wilson »

I figure I will keep increasing the pressure in 5 lb increments until something happens. Just wanted to make sure I knew what was supposed to happen
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Post by tyang »

Tom Wilson wrote:I figure I will keep increasing the pressure in 5 lb increments until something happens. Just wanted to make sure I knew what was supposed to happen
BE CAREFUL!!! I wouldn't add pressure if it's getting caught on the last bit of distance for the piston to come out of the bore. What happens is the top edge of the piston bore rusts, and creates a ridge that keeps the piston from sliding out. The seal catches on this rust ring and doesn't move forward. If it doesn't simply pop out, you may want to consider doing what Jimmy Riff suggests with using grease. Hydraulic pressure is not compressible and will not violently release when the seal finally passes the rust ring. The other option is to take it to Karps. I've used them for my Sunbeam's booster years ago, and was satisfied.

When doing this with air pressure, wrap the caliper well with a towel to contain the minor explosion. This procedure is only a recommendation and proceed at your own risk!!!

Tom
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Post by xs10shl »

Tom are you nickel plating your caliper frames as opposed to silver zinc plating them?

Also, for anyone who is interested, mapp gas will burn hotter than propane and is (I think) much easier to use. Buy the yellow bottle at home depot instead of the blue one, and keep in mind you'll need a different torch - you can usually buy a starter kit with torch included. I think it's a little more expensive, but worth it.
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Post by Tom Wilson »

Nickel seems to be the way to go. I have a meeting tomorrow near Karp's Brake Service, so I am going to drop by and check out their facilities. Their web site looks pretty good and Tom Y has had work done there. Lets see what they have to say about Nickel vrs Clear Cadmium vrs Silver Zinc.

I still have to disassemble and blast the brakes before sending them out, so I have time to look into more brake guys and techniques.

As for the MPP gas, that is what I have. It is supposed to be hotter than propane. Home Depot also has a 4' hose for it, which makes holding the torch easier than when it is directly attached to the bottle.
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