aluminum S brake caliper question

rfuerst911sc · 03-14-2009, 09:40 AM

Today I scored what I believe are aluminum S brake calipers at a swap meet for a good price. They are definately aluminum with 3.5 inch mounting ears and they say ATE on them. They are visually in great shape and I was able to remove all 4 pistons. However the crossover tube is missing from both. I hope that is the correct term, it's the metal line that feeds fluid from one side to the other. So where do I get those? Is there a part number for them? I believe the calipers have 48mm pistons which will work well on my 914 GT clone. Any feedback on these calipers is appreciated.

356RS · 356RS's Garage

Crossover tube is right. There is a left part# and right part# I think. Stoddard has them.

Flieger · Flieger's Garage

Ah, S calipers and 914/6s- you must talk to Eric Shea at PMB Performance: www.pmbperformance.com

rfuerst911sc · 03-14-2009, 12:28 PM

Quote:

Originally Posted by Flieger

Ah, S calipers and 914/6s- you must talk to Eric Shea at PMB Performance: www.pmbperformance.com

Oh yea I'm familiar with Eric. I may end up sending these to be refurbed by him. Thanks

RoninLB · 03-14-2009, 01:02 PM

I installed ss pistons in mine.

DonNewton · DonNewton's Garage

Had them on my 914-6 (conversion) and took them off after 9 years of track work. They finally got so that they would flex too much. Went to Boxster front calipers! My, what a difference!

joefrantz · 03-15-2009, 06:14 PM

When I tried to order crossovers from Stoddard I found that they only sold them as one size fits all when, in fact, the ones that I was trying to replace were left and right sided. I guess you could re-bend them, but they're not particularly cheap, so beware. You might be able to get a good parts store to make a set for you alot less money.

Joe

shbop · 03-15-2009, 08:37 PM

Eric can get the crossovers. He's a nice guy, and does beautiful work.

JohnJL · 03-15-2009, 08:55 PM

Don,
I have S calipers on my 71 and the brakes dont feel "right" even after rebuilding, new MC, lots of other fiddling.

I finally gave up and took them to the local race shop who replicated everything I did then came to the conclusion that the S calipers were just "worn out" and that they have developed some flex.

This doesnt seem right to me...do calipers "develop flex?"

rfuerst911sc · 03-16-2009, 12:50 PM

Stoddards list 2 part numbers for the crossover tubes a left and right. So does Pelican.

shbop · 03-16-2009, 04:44 PM

Have you seen this thread?

http://www.early911sregistry.org/forum/showthread.php?t=18610&highlight=rebuilding+calipers

djpateman · 03-18-2009, 10:22 AM

Quote:

Originally Posted by JohnJL

This doesnt seem right to me...do calipers "develop flex?"

Not likely unless they are cracked. I do know that a lot of what has been perceived as caliper flex is actually the floor flexing where the MC is mounted.

Eric_Shea · Eric_Shea's Garage

Flex is basically Internet BS...

Go to an HSR 2 liter challenge. Watch them race. Hit the pits. Marvel at their "very" cool cars. Check out the calipers while you're at it. Report back. Let me know if you drive that aggresively, stop that fast and if your car can beat any of those guys on the track.

Vic Elford seemed to do just fine in the 908... but hey; that's just Slick Vic.

Next myth?

Tom C. · 10:06 PM

Here's a bit of Eric's work . . . very nice in my opinion. Can't see in the photo but they have a mirror finish with all the raised detail left in perfect original condition.

RoninLB · 04-09-2009, 11:45 PM

gotta say it's nice to learn something about the S-

I few weeks ago pics were posted of the 3 generations of the S-caliper.

I'm removing and selling my S-calipers w/ss pistons very soon. I think they're the 3rd generation.

I'm going bigger.

Eric_Shea · Eric_Shea's Garage

I put together a thread on that subject:

http://www.early911sregistry.org/forum/showthread.php?t=20186&highlight=s-caliper

Here's a picture of the basic outcome:

There's a few "other's" I've found (Like Thomas' green dichromate "early" calipers and the crossover calipers with the indents but no "X") but these are the basics.

Note the later style S-Caliper has a 910 caliper style nose, while the early S-Calipers are made off the same mold as the 908 caliper.

chris_seven · 04-13-2009, 06:17 AM

Quote:

Originally Posted by Eric_Shea

Flex is basically Internet BS...

Next myth?

I always wondered how caliper flex could reduce pad clamping force unless Mr. Newton was mistaken.

How about the cast in holes for 'cross-drilled' rotors?

Plavan · Plavan's Garage

I do have to say that I have witnessed some aluminum calipers that have "flexed". The pads would wear at a wierd angle. These were on race cars. I have the later model Aluminum calipers with the "X" and I have not experienced flex at all. I'm wondering if there is a change in reinforcement on the later calipers?
My .02 cents

djpateman · 04-13-2009, 10:32 AM

Chad, if you look at the caliper on the left in Eric's photo above you can see that the late nose was much broader than the earlier varieties. This would make it stronger. The "X" denoted an earlier change in design.

Eric_Shea · Eric_Shea's Garage

Quote:

Originally Posted by Plavan

I do have to say that I have witnessed some aluminum calipers that have "flexed". The pads would wear at a wierd angle. These were on race cars. I have the later model Aluminum calipers with the "X" and I have not experienced flex at all. I'm wondering if there is a change in reinforcement on the later calipers?
My .02 cents

Check the factory manual. There's a page dedicated to caliper issues. Slanted pad wear is not caused by S-Caliper flex. It goes like this:

Slanted Pad Wear:

1. Check 20 degree piston step down
2. Replace brake pads
3. Change cross spring
4. Adjust wheel bearing clearance
5. Check disc and caliper mounting, check alignment of mating parts
6. Check disc shields
7. Clean corrosion from brake cylinders
8. Check piston progressor (piston seal)

I'm not trying to bust anyones berries... it's just that these are the stories that perpetuate the myth (I've heard that one before and seen many slanted pads... on steel calipers) . You have a much greater chance of feeling your floor flex by the M/C than you do your calipers. If you have slanted pads you have much more to be concerned about than caliper flex.

The "X" denoted a piston change. The best rule is the color (for the most part). The greenish dichromate will usually be that later style with the 910 nose. I really don't know why they switched back to the 910 style nose. It does look a bit more robust. It's just funny, the same camp complaining about S-Calipers would be all over the Internet bragging about their 908 calipers (if they could find and afford them).

(psssssssssssst... don't tell them; they're the exact same thing.)