Front caliper options Options

[Hammy]

Well my mechanic says something about the front calipers aren't releasing the brakes all the way. What could this mean? I've been reading about the BMW 320i caliper replacement. If I were to buy the BMW calipers, could I have a local brake shop put them on (we know nothing about this stuff)? Or is it too complicated? (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

[brant]

Its not too complicated, but cheaper and just as good to rebuild yours.

have your shop rebuild the stock calipers...
or buy rebuilt ones from a FLAPS and then trade in your old ones as cores.

[skline]

Sounds like you got some sticky calipers. I am going to use the Volvo calipers on my white car like I did on the Chalon. They are $150.00 for the set fully rebuilt from the parts store. Use a 1/8" spacer and you are good to go. I would of course remove the rear proportioning valve and run a larger M/C but I am not 100% sure if that is needed. I have not changed out the one on the Chalon yet and it seems to stop just fine.

[Hammy]

Well won't the BMW calipers give better stopping power? I figured since the front calipers need a rebuild, I'd just have them exchanged out instead.

[brant]

Zack,

its a highly debated topic around here.
but most of the bmw brake conversions Do Not use vented rotors...

so they don't increase the thermal mass and can overload the stock rotor.

My opinion is that a good stock caliper (rebuilt) with good pads and fluid will be very adequate and maybe just as good as a bmw caliper.

(plus cheaper and easier)

b

[Hammy]

Ya thanks. It's in the shop now and I'm going to have them rebuilt.

[jim_hoyland]

Volvo Calipers ? What models brakes are a direct fit ? I've got a volvo and have always liked the braking....Hmmmmmm

[Aaron Cox]

QUOTE (jim_hoyland @ Feb 8 2005, 08:01 PM)

Volvo Calipers ? What models brakes are a direct fit ? I've got a volvo and have always liked the braking....Hmmmmmm

240's had non vemted and vented 4 pot calipers

[SpecialK]

I've got a '74 with stock front calipers and MC, and a '73 with BMW 320i calipers and a 19mm MC, but since neither run at this time I'll withhold judgement until they do......Then we'll end this "this set-up" "that set-up" BS for good......(at least in my mind) (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[jim_hoyland]

and correct spacing ?

[scotty914]

well i currently have the 320 i brakes on mine

and to argue the " over heat/load the front brakes" thing it takes x amount of friction to stop, so weither the pads are stock or bigger does not matter. same amount of heat either way, it does not take more friction to stop a car with bigger pads just less hydrolic pressure. but for general street use either way, but for track i would go vented.

[914GT]

The 320i brakes are working great on my car.

[skline]

Ok, in all fairness, I am running vented front rotors on the Chalon. However, Bernbomb is not running vented rotors and he is running the 240DL calipers on his car. He likes them and has not had any problems with them as far as I know. He has had them on there for more than a year now. I hope he chimes in here and says something. The pads are nearly twice the size of even the BMW pads.

[Aaron Cox]

i got a set of volvo 240 calipers to throw on my car ..... will it clear the wheels..... (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif)

also... do they sit all the way on the rotor?

[Brett W]

Alright here is the skinny onf the Volvo Calipers:

Come from a 190 and 240 early 80s to early 90s
There are two kinds. Vented and non Vented.
The calipers I have are Girling, have not inspected the ATEs.
They have a 3in bolt pattern on the calipers.
The non vented calipers sit .050 off the centerline of the tock rotor, towards the wheel. You will have to shim them back a little.
The vented calipers will work with a .810 rotor.
Both calipers are the same as far as major dimensions . The vented caliper is not machined as much so it is thicker.
All volvo calipers are dual circuit. They will require an adapter block or a set of custom bent hardlines to be fed from a standard master.
The calipers will overhang the edge of the pads. They will work perfectly with an 11.75 aftermarket rotor. You can either machine the pads or take just deal with the over hang.


I have an aftermarket aluminum hat and vented cast iron 11.75 x .810 rotor that will work perfectly with the Vented caliper on the stock 914-4 cylinder strut (haven't test the early struts). To make it fit, the hub centric ring will have to be machined from the hub or open the hat up to clear the ring. (did want to mess up my prototype). The hat will slip over the existing hub giving you a 1/4 wheel spacer. Don't know if Fuchs will clear the fender wells, yet. I am still in the prcoess of developing this one for my top secret project but will be testing in a street car soon. I figure it will need a 23mm master cylinder. Might be able to use the stock 914 front calipers on the back or even run the Volvo calipers on the back. Haven't gotten that far yet. I haven't tested wheel fit as my steel wheels have all kinds of room for calipers. Don't know about alloys yet. There is plenty of material to clearence the caliper though.

Questions?

[GBallantine]

For those who have done the 320 caliper conversion with a 19mm master and a brake bias control. Is there any difference in the pedal effort or feel? ( softer or the same)

GB

[Eric_Shea]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) w/Brant.

I'm not panning brake conversions. I simply like to look at them as a "whole" meaning front and rear. The BMW conversions I've heard mentioned on this board all seem to have positive results. My concerns would be brake bias in an emergency situation.

Let's face it gang... they may not have blessed us with massive horsepower but Porsche is one of the best, if not the best production oriented company on the planet at "brakes". A well sorted "stock" brake system will still stop your car faster than most cars behind manufactured "today". Rebuilt calipers with some of today's pad technoligies can make your car scream to a halt. This is a "very" well balance system. Including the proportioning valve we all love to hate.

If you're adding more "power" then by all means add more brake. You can look to Porsche for answers there as well. I added an early 911RS/930 system to my car because the intended engine rebuild would be in the same hp range.

To the original question:

1. Pistons can stick. The top of the pistons can get a bit crusty, especially if the boots are torn etc. The rubber seal can bind if the car's been sitting for a while. Make sure they hone your cylinders and polish your pistons during the rebuild process. (I think there's a Beavis & Butthead joke somewhere in that last sentance... (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif) )

2. The factory rubber lines can deteriorate and swell internally allowing fluid to pass through under the extreme pressure of pedal application yet will not easily allow the fluid and pressure to release the pad... hence sticking.

Don't have your calipers rebuilt without investing another $12.00 per side in new factory rubber lines. Good luck.

[Rusty]

Stock calipers work well. You can rebuild them yourself in a little while, or have your mechanic do it. The kits are readily available. Otherwise, your local auto parts store should have rebuilt calipers available.

When was the last time your rubber brake lines were replaced? They swell internally with age. When you stomp on the brake, fluid is pressed through and the brakes lock. When you release, there's no corresponding pressure to force the fluid back out of the caliper - the caliper stays "stuck".

Change the rubber lines (if they're suspect) and flush the system.

-Rusty (IMG:http://www.914world.com/bbs2/html/emoticons/smoke.gif)

[type47fan]

How about these?

[bernbomb914]

I have had good luck with the Volvo calipers. I have solid rotors (stock) a 19mm M/C and no porp. valve. They fit the riveria wheels with a little sanding on the belt sander and fit the ATS wheels also. they stop much better than the stock brakes but I am not racing and use the car as a daily driver.