questions about my car. Stuck calipers, headlights etc Options

[dabird]

I'm 5 days in as a 914 owner and I have a couple of questions.

1. My headlights have a mind of their own when you turn them on off. The just continue to flip up and down for about 30 seconds before finally settling in the up or down position. sometimes the do it together. sometime only one side. My first thought is a ground issue but maybe someone else has had the same issue and knows the cause?

2. My biggest issue with the car is the rear calipers are dragging. I was told the parking brake was stuck when I got the car but it appears that pistons are stuck dragging against the rear rotors. The cables for the parking brake are moving the levers but you cannot get the car to budge in neutral with the parking brake on or off. I plan on getting rebuilds from PMB but after hearing that a lot of 914's are rolling around with inoperable rear brakes, I'm wondering if i can back the pistons off with the adjusters and be able to drive the car in the meantime?

3. I've found someone near me parting a 72. I'm interested in a few parts and I'm wondering how much difference there is between the two? Will the front valance from a 72 fit on a 74? I'm assuming all the lenses (turns, tails etc) are the same?

Here she is tucked safely in her new home

[rhodyguy]

Lenses are all common except for the coloring for various countries. FIX brakes, drive car.

[stugray]

If the flex lines are really old, they can swell inside pinching off the flow of brake fluid.
Fluid goes in but cant get out so pistons drag.

Happened on my first 914, but on the fronts.

[dabird]

If the flex lines are really old, they can swell inside pinching off the flow of brake fluid.
Fluid goes in but cant get out so pistons drag.

Happened on my first 914, but on the fronts.

hmmm, i will look into that. thanks

[jmalone]

Replace your brake lines. Send your rear calipers to PMB performance Eric Shea's business for re-manufacturing. He can also do your fronts but you can as well (the rears are a bit tricky). Eric does great work has tons of knowledge and is a nice helpful guy. ( He has probably done brakes for half the people here. Have fun with your great little car! (IMG:style_emoticons/default/biggrin.gif)

[somd914]

A lot of 914 owners running around w/o rear brakes?!

I can't see where backing off the adjusters would help with a stuck caliper - basically all the adjuster does is set how far the pistons will retract - stuck is stuck... Agree hoses can be the culprit, but from my experience it is typically the caliper, but no matter, replace the hoses as preventative maintenance.

To the best of my knowledge a '72 valence will fit your '74. The vast majority of parts were the same or at least interchangeable between the years outside of engine and transmissions where differences definitely exist.

[Mblizzard]

I have to agree with getting Eric to do the brakes especially the rears. I hated the cost but more times than once I have had to depend on the quality work Eric provides and in the very short long run I know I am money ahead.

Cool car!

If you were not going to drive the car, you could remove the rears and compress the pistons with a C-clamp. That would allow you to move the car more easily but once you do that the seals will likely be damaged from being forced by the corrosion and the car would not be safe to drive.

[pdlightning]

Replace your brake lines. Send your rear calipers to PMB performance Eric Shea's business for re-manufacturing. He can also do your fronts but you can as well (the rears are a bit tricky). Eric does great work has tons of knowledge and is a nice helpful guy. ( He has probably done brakes for half the people here. Have fun with your great little car! (IMG:style_emoticons/default/biggrin.gif)

I agree with going to Eric. I bought my 308 style calipers from him and they are very nice. As far as the price, what is your safety worth?

[falcor75]

https://www.youtube.com/watch?v=dm_DnizKOZM

This video is a good start, Watch it and maybe you feel you're up to doing the job yourself, its not very hard provided you have some wrenching experience and the right Tools.

[dabird]

I was thinking about my brakes while driving to work today. Since my pistons are dragging against the rotors it makes sense that the cause could likely be internal swelling of the soft brake lines. I'm thinking a way to test for this would be to open the bleeder and that should release the pressure and allow the pistons to slide back....does that seem like it would work?

[Mblizzard]

I was thinking about my brakes while driving to work today. Since my pistons are dragging against the rotors it makes sense that the cause could likely be internal swelling of the soft brake lines. I'm thinking a way to test for this would be to open the bleeder and that should release the pressure and allow the pistons to slide back....does that seem like it would work?

This is a new concept to me regarding lines swelling which I have a hard time visualizing. If you think of brake fluid as an uncompressible fluid it basically performs like a rod that transfers the force you put on the pedal to the piston in the caliper. You get a force multiplication by the fact that the psi you put on the pedal is increased by the surface area of the piston.

Others may have more experience with this but unless the lines have completely swelled shut, I would find it hard to see that the rubber wall could hold back sufficient pressure to keep the piston pressed against the rotor indefinitely. I would think that the pressure would have to return to an equilibrium point after a certain amount of time and the pistons would move back. If that was not happening then opening the bleeder screw would release the pressure if it was present. Worth a try.

But I bet if you do it that wont be the problem. There is a procedure for setting the clearance on the pads but as stated earlier if the pistons are stuck they are stuck.

I would get a bunch of brake fluid and flush the system noting the condition of the fluid that comes out. If it is dirty and full of grit then you can be pretty sure internal corrosion is your problem.

[69telecaster]

I was thinking about my brakes while driving to work today. Since my pistons are dragging against the rotors it makes sense that the cause could likely be internal swelling of the soft brake lines. I'm thinking a way to test for this would be to open the bleeder and that should release the pressure and allow the pistons to slide back....does that seem like it would work?

Yes...and it's an easy test. If they're the original hoses, you should replace them anyway, and flush out all the old fluid. You may find that the hard lines need replacing, too.
If you don't have any yet, get some jack stands... (IMG:style_emoticons/default/happy11.gif)

cm

[Larmo63]

Regarding the headlights, my car had sat also, and it took a few days for the lights to "synch" themselves. They work as they should now. Keep trying them, they should work themselves out. (IMG:style_emoticons/default/welcome.png)

[stugray]

I was thinking about my brakes while driving to work today. Since my pistons are dragging against the rotors it makes sense that the cause could likely be internal swelling of the soft brake lines. I'm thinking a way to test for this would be to open the bleeder and that should release the pressure and allow the pistons to slide back....does that seem like it would work?

This is a new concept to me regarding lines swelling which I have a hard time visualizing. If you think of brake fluid as an uncompressible fluid it basically performs like a rod that transfers the force you put on the pedal to the piston in the caliper. You get a force multiplication by the fact that the psi you put on the pedal is increased by the surface area of the piston.

Others may have more experience with this but unless the lines have completely swelled shut, I would find it hard to see that the rubber wall could hold back sufficient pressure to keep the piston pressed against the rotor indefinitely. I would think that the pressure would have to return to an equilibrium point after a certain amount of time and the pistons would move back. If that was not happening then opening the bleeder screw would release the pressure if it was present. Worth a try.

But I bet if you do it that wont be the problem. There is a procedure for setting the clearance on the pads but as stated earlier if the pistons are stuck they are stuck.

I would get a bunch of brake fluid and flush the system noting the condition of the fluid that comes out. If it is dirty and full of grit then you can be pretty sure internal corrosion is your problem.

The calipers work by having a tiny amount of "kickback" that is provided by the elastomer gaskets on the piston.
Under normal operation the pressure pushes the piston towards the rotor, and when you let off, the force of that rubber elastomer pulls the piston back the few thousandths that keeps the pads from dragging on the rotor.
It does not take much back pressure to keep the piston from pulling back.
The symptom of my problem was that after a long highway drive, you would go to use the brakes and they would go to the floor until you pumped them.
I finally checked and found after a long drive that one of the front wheels was really hot.
The brake was dragging and after a long time, it would boil the brake fluid creating a "gas pocket".
I rebuilt the front calipers three times to try to solve the problem and couldnt figure it out until I tried to purge the lines by pumping them with no calipers installed.
The side that was dragging would barely trickle out while the other side would shoot fluid 10 feet.

I replaced the lines and the problem went away.

[dabird]

my symptom is at least one of the rear calipers is not releasing off the rotor. maybe it is a parking brake issue but i had someone pull the lever and it appeared that the cables are moving the parking brake actuators. i haven't had all that much time to look into it. i'm hoping to dig deeper this weekend

[dabird]

so i put the car up on jackstands and dug into the rear brakes a bit today. cracking the bleeders did nothing. tried tapping on the actuators to see if if i could if the parking brake was stuck and would pop loose. no dice. it appears i'm looking at buying rebuilds from PMB. one thing i did notice seven though my car is a 74 it has the earlier calipers with the ribe bolts and only one bleeder. is there any reason to switch to the later style other than not having to deal with the ribe bolts?

[Mblizzard]

Eric would know for sure bur when I was having trouble bleeding the brakes the top bleeder came in handy. I would think going back with the right year would be the thing to do.

[stugray]

I just took apart 4 front calipers.
Two of them looked like fairly new rebuilds.
Some of those 4 pistons could be pressed in with hand pressure.

The second pair of calipers looked like they had been sitting in a barn for 30 years.
I had to use a c-clamp to even budge the pistons at first and it took a lot of cycles to get them freed enough to take out.
The inside of those calipers looked like mud and were clearly badly contaminated.

So if they are old and have sat for many years (even on the car) without being exercised the piston(s) might be seized.
And I believe that by sitting for that long without heating up, the brake fluid absorbs water and corrodes the brake system.
Inactivity is bad for these systems.

[dabird]

This car has only been sitting for about 6 months. It was being up until last fall before it was garaged for the winter

[stugray]

I would consider selling my newly rebuilt rear calipers with new pads as soon as I finish replacing them with front calipers (next week maybe?)

Or I have two other sets of rear cores I could rebuild.
Rears are harder to refurbish than fronts however.