Front Brakes Dragging, wheels don't spin free Options

[7TPorsh]

Tried looking in search...

I changed out the following;
- Front brake rotors
- Front bearings and seals
- Front pads

I tried to push back the piston enough to get the pads in...ending up tapping them in but not too much effort. I noticed that it was tight. Thinking it will loosen up, i finished the job.

I get the car on the ground and out on the road a little and realize that the car just doesn't roll...i am working against the brakes. Brakes didn't 'adjust" and are still really tight. Lock nut is not overly tightened.

[Mike Bellis]

Technically disc brakes should drag a little. with the wheel off the ground, spin the wheel. it should stop after one revolution.

If your car does not roll at all? I would check for caliper alignment, bearing seating or some physical obstruction.

You may have the pistons off set from eachother. one side with too mush pressure to the disc. They should equalize after some time.

[914Sixer]

Jack up each wheel and spin them. Find out which caliper is sticking. Check your venting on the real calipers.

[7TPorsh]

off the ground they don't spin. I have to grab it and turn...it's really tight. Both sides are the same.
The brake pedal works and stops the car fast when driving; but I have to floor it in 2nd gear to keep it at 25mph.
Venting??

[Mike Bellis]

off the ground they don't spin. I have to grab it and turn...it's really tight. Both sides are the same.
The brake pedal works and stops the car fast when driving; but I have to floor it in 2nd gear to keep it at 25mph.
Venting??

Remove the callipers. Do they spin? While spinning the rotor, tighten the lock nut until it stops spinning. back the nut off 1/4 turn. install the calliper. slam on the brakes a couple of times. try to spin the wheel.

[dr914@autoatlanta.com]

and make sure that the pedal itself is not sticking due to swelled plastic bushings and that the rubber flex lines are not clogged

[etcmss]

did the bearings go on easily and is the rotor fully seated? Lastly is there clearance in the brake pad to caliper?

[bandjoey]

Are the clearance clips in place on the pistons? They automatically set the clearance on the front. Rears have a screwin vent clearance.

[Eric_Shea]

Are the clearance clips in place on the pistons? They automatically set the clearance on the front. Rears have a screwin vent clearance

(IMG:style_emoticons/default/huh.gif) (those are piston positioning clips meant to keep them at 20 degrees)

Gary, check the softlines. They swell internally with age. This allows pressurized (by your foot) fluid to go by and only slowly leak back into the MC/res. location. You can tell if the car rolls after it sits for a while.

Your description "ending up tapping them in" usually means the pistons are coked with brake fluid schellac. It's a combo of gummed up fluid and rust on the piston walls. the only way I know to get that fixed is to rebuild them. All of it will come off with a polishing wheel or a vibratory polisher (usually).

Check the pedal as George suggests. I have had this happen a couple of times but, you can feel it and, you can diagnose by pulling the pedal back with your toe. If you have to/can do that then it's you pedal bushings.

Good luck.

[etcmss]

Eric -are you saying the hose(s) actually get a buildup and act like an orifice? (ok going in but slow releasing?)

[jmill]

Eric -are you saying the hose(s) actually get a buildup and act like an orifice? (ok going in but slow releasing?)

That's what he's saying, kinda. He was talking internal swelling but basically the same outcome. It's happened to a bunch of guys. Problem gets fixed when they change their lines.

[7TPorsh]

I don't think it's the lines but will look. If the lines then wouldn't the pressure subside at some point and loosen up?
Feels more like the piston isn't going all the way in (it looks like it is) of the thickness of the new rotor and pads it too much?

I will try to loosen the calipers with the pads in and see what happens.

[underthetire]

Ok, just gotta ask here. New pads (thicker than old ones) new rotors (thicker than old ones), so...

If there is varnish at the back of the piston bore on the calipers, and he had to force them back, would it not make sense that the piston could now be frozen in the caliper bore? I would think if you were doing pads,rotors,and bearings, it would be well worth the 12 bucks or so per kit to re build the calipers, and put new lines on. (from Eric) DON'T BUY THE EBAY KITS. they don't have everything you need.

[ahdoman]

another thought - If, when you took the calipers off the struts, you let them hang by the hoses then I would suspect that you might have crimped something. What happens when you loosen the bleeder? Does fluid come squirting out or just "burble" out?

[Cap'n Krusty]

'70-'71 and most '72s took the T4 rotor. Late '72s and '73-'76s took a 914 rotor. The offset is different, and they do NOT interchange. The struts and calipers are different as well. It is good to keep the parts matching, as failure to do so will cause just this scenario. Beyond that, those brake hoses may well be close to 40 years old, may have seen very few brake fluid changes, and should be replaced anyway. They, too, can cause what you're seeing. For economy, longevity, and safety, nothing beats using the OE style rubber hoses. Good luck!

The Cap'n

[Eric_Shea]

The struts and calipers are different as well. It is good to keep the parts matching, as failure to do so will cause just this scenario

The caliper offset is quite different. I doubt they would even bolt up.

Feels more like the piston isn't going all the way in (it looks like it is) of the thickness of the new rotor and pads it too much?

This is a clue. This happens when a caliper has sat for quite a while with water infested fluid. A build up of dried fluidgunk (yes, fluidgunk... work with me here) becomes ferrous oxide in nature (read: rusty). This rusty clump can gather at the bottom of the back of the piston bore preventing the piston from going back all the way.

[sean_v8_914]

frozen caliper pistons. dark brown nasty brake fluid. internally rotten rubber lines
...go fix it already

[ME733]

......AND when everything mentioned has been checked or replaced, HOW ABOUT INSTALLING some NEW EXPANDING SPRINGS . those are the metal clips, looks like a cross, held in place by the pins, in the calaper, they perform the function of pushing back against the pad, moving the pad AWAY from the ROTOR. 30-40-year old ones are simply DEAD.(5-10 year old ones are dead also), They provide the necessary pressure to overcome the master cylinders built in 3-4 psi pressure. With everything as it should be there should be NO wheel drag on the ground rolling. IT should Roll with a push. Mine does. BTW I generally replace the "EXPANDING SPRINGS about every 5-6 years. they are metal, fatuge with use and heat and loose their tension.....MURRAY.

[7TPorsh]

......AND when everything mentioned has been checked or replaced, HOW ABOUT INSTALLING some NEW EXPANDING SPRINGS . those are the metal clips, looks like a cross, held in place by the pins, in the calaper, they perform the function of pushing back against the pad, moving the pad AWAY from the ROTOR. 30-40-year old ones are simply DEAD.(5-10 year old ones are dead also), They provide the necessary pressure to overcome the master cylinders built in 3-4 psi pressure. With everything as it should be there should be NO wheel drag on the ground rolling. IT should Roll with a push. Mine does. BTW I generally replace the "EXPANDING SPRINGS about every 5-6 years. they are metal, fatuge with use and heat and loose their tension.....MURRAY.

Actually i don;t have these springs since they broke when I took it all apart. Where can I get them? I only found places with 911 ones and hey are different I think.

[etcmss]

Pelican-- http://www.pelicanparts.com/catalog/shopca...d_pg2.htm#item7

or AA http://www.autoatlanta.com/porsche-parts/p...arts/602-00.php