Early 911/912 "M" calipers, direct bolt on to a '70 914? Options

[tradisrad]

I am looking for an upgrade to my front stock calipers and the "M" caliper for solid rotors seems to be a good choice. The car has a 19mm master cylinder and the braking could be better and instead of replacing the master cylinder with a 17mm I thought I'd upgrade the front calipers.

From what I can tell early 911/912 calipers for solid rotors will be a direct bolt on to the early 914 strut. I also think they use the same brake pad.

Has any one done this or can someone confirm that they will be a direct bolt on and is the pad size the same?
thanks
-Rob

[SLITS]

Eric has to chime in ... I think the offset is different and the rotor won't center in the caliper.

Early BMW calipers will bolt on an early strut and center correctly. There are threads about that "upgrade". To fit later cars, I remember the mounting ears have to be shaved 0.125" on the inside AFAIR. Don't remember the years of the Beemer either.

[ArtechnikA]

I am looking for an upgrade to my front stock calipers and the "M" caliper for solid rotors seems to be a good choice. The car has a 19mm master cylinder and the braking could be better and instead of replacing the master cylinder with a 17mm I thought I'd upgrade the front calipers.

MC won't give you more or less braking, unless you're in track service and you run out of volume due to lots of heat. The 19mm will give you a stiffer pedal, the 17 may let you modulate better ('more feel').

IMO - if you want better braking, just get a better class of pad. Porterfield R4S are the hot setup. A solid-rotor 911/912 caliper will be OLD, and cast iron. You're better off with what you've got - just use a decent pad. I had an early ('65) 912 and I don't think its brakes were even a little better than a 914's...

For a real update, Aluminum vented-rotor 4-bolt 3" calipers from our current classifieds.

[tradisrad]

My understanding of the 19mm master with the stock calipers is there is less force on the brakes than with the 17mm. I read this in several places like the Lapuwali write up on brakes. Therefore if I put larger calipers or a 17mm master I will increase the force on the brakes.

I am running Porterfields. It may be less expensive to upgrade the caliper especially if I can use my existing pads.

I also found a brake write up on the bird board that says the "m" calipers will bolt right on the early struts and use the same size pad. I checked both pad (911 & 914) part numbers at PMB and they are the same. The Brembo brakes in the classified are said to bolt on, but I can't really find a second (or third) confirmation that they do.

[914Sixer]

Get a stock 17mm master cylinder and put some GOOD pads on all four calipers. Use stock rubber lines too.

[Eric_Shea]

the "M" caliper for solid rotors seems to be a good choice

They bolt right on. Good choice? Same size pad with a 48mm piston vs. a 42mm piston. You're not gaining anything in friction. Just screwing up the bias with the rears.

less force on the brakes than with the 17mm

Well... it actually takes more force to operate the pedal but, that's negligible at this point. I would replace any 17mm with a 19mm at this point (if it needed to be replaced).

IMO - if you want better braking, just get a better class of pad. Porterfield R4S are the hot setup. A solid-rotor 911/912 caliper will be OLD, and cast iron. You're better off with what you've got - just use a decent pad. I had an early ('65) 912 and I don't think its brakes were even a little better than a 914's...

(IMG:style_emoticons/default/agree.gif) What she said. (IMG:style_emoticons/default/biggrin.gif)

914 brakes in tip-top order with killer pads should rock any narrow body world. Are they gummed up? Do they have old soft lines? Is the venting clearance set on the rears (most are inoperable)? Did you bed the pads? Even old pads can be re-bedded and you'd be surprised at the difference.

Those Brembo's in the classifieds are the hot set-up but, you'll need vented rotors (or, there's a guy selling his that have the spacers removed... bolt on for your car. PM me for his details). The problem you'll find is, there's a "lot" of pad there for a solid rotor. Time to get some cooling in there.

Most people would benefit from a thorough system rebuild (top to bottom), new pads and new tires.

Best... E.

[brant]

the right pad makes stock calipers VERY VERY good.

most people the "upgrade" their calipers are really benefitting from a rebuilt "system" more than any improvement in in caliper over stock

buy good pads (RS4)
new lines
and quality brake fluid
if you have any rotor warp take care of that too.

[tradisrad]

Thanks for the replies.
I do have good pads, R4S, in the front only and I was told (by Rich at HPH) that I dont really need them in the rear; should I order some? PMBseems to have good prices.
All 4 calipers were rebuilt 2 years ago, no pitting in the bores or on the pistons, new seal kit from PMB & braided lines. Venting clearance is as close to .004 as I could get it; recently double checked.

I did not bed my pads. I'll give that a try. I probably could use new tires.

[Eric_Shea]

Not trying to sell a set of pads but... 914 brakes are very well balanced. I like the same compunds front and rear.

Here's the bedding procedure:

http://www.pmbperformance.com/Bedding.html

[Dave_Darling]

Remember: Brakes stop the wheels.

TIRES stop the car.

--DD

[tradisrad]

Eric, I did pick up some rear pads last night. I always try and purchase local if I can even though your prices are about $10 cheaper. I appreciate your expert opinion. I found a second set of rear rotors in my stash that look to be unused and I will put them on with the pads.
I have only bedded pads once before and never on my 914, so i' ll give it a go. I will also bleed the system and report back with the results. I don't know if I'll finish today as the family and I are going to try and learn to Eskimo roll our kayaks this afternoon.

Thanks
-rob

[jmill]

PMB seems to have good prices.

If he's got it or can get his hands on it his prices rock (IMG:style_emoticons/default/piratenanner.gif) I saved a boat load of cash buying from Eric.