TheSamba.com :: View topic - Front left caliper sticking (yes I searched)

Tue Jan 27, 2015 8:59 pm

Sorry this is pretty long...

I used my head. I used the search. Now I'm hoping to use the collective experience of the Samba. I often work on my van myself, but this time of year I can't really work on it on the street in NYC, so I take it to a mechanic.

1990 tintop. I had a pulse in the pedal, which in my experience means a warped rotor, checked with the e-brake just to see if it was the drums. no pulse with e-brake.

Mechanic confirmed that the rotors were shot (they were) so replaced them with German rotors his (the mechanic's) parts supplier had on the shelf from way back. the old left rotor was worse than the right (this should have been an indicator of something else, but at the time wasn't)

With the new rotors had some weird chirping, dragging etc seemed to be coming from left front. Brakes felt OK, then pulsing returned. went back to mechanic who noticed that the left caliper guides were trashed. I assumed this was the cause of the first problem and figured, OK time to replace the calipers. ordered rebuilt calipers and had them installed. pulse still there.

Returned to mechanic, who removed the rotors, had them checked, told me they were true and not warped, put it back together. pulsing still there. At this point I think the new rotor is warped and should get turned

Side issue: Starter died Friday night before it snowed, couldn't bring myself to lie in the slush to replace it, so yesterday morning as the supposed great Blizzard was approaching I had AAA tow me to the mechanic and had him install the spare new starter I had.

While the van was on the lift I asked if we could look at the issue with the brakes, sure enough the left from wheel doesn't spin as free as the right, removed the wheel and pushed back the pads with a screwdriver and voila it spins freely. Mechanic suggests replacing the hose.

I replaced the hoses ~18mo ago with SS braided lines. So after researching here what I'm trying to figure out is a next step.

Has anyone had the same issue with SS lines as with older rubber lines?

Could it be the proportioning valve? which I admit I don't fully understand or know if this could be the problem.

I guess it could be two bad calipers, but this seems unlikely. If the snow melts or I can find a decent spot to park it I could remove the wheel and try to lubricate the guide pins etc on the caliper.

I saw reference to the Master Cylinder potentially causing this problem, which I had replaced ~3 years ago I believe (my notebook is in the van and it's parked 3 blocks away and it's 20degrees out.

So what would you check next?

Wed Jan 28, 2015 12:10 am

I would check that the wheel lug nuts are not over-tightened, that's what I would check.

Wed Jan 28, 2015 1:13 am

The proportioning valve is to make the front and rear brakes both work in conjunction with each other. It sort of times the braking between the two. I don't see that being the problem.
Maybe your new hose got contaminated somehow?

Wed Jan 28, 2015 3:19 am

Are you guys cleaning and lubricating the caliper slides and testing it for easy motion ? Many folks neglect this. I have had to remove junk rusted onto the slides with a chisel to get a smooth caliper slide surface on older cars.

Wed Jan 28, 2015 5:27 am

Levi
I removed the wheel when I pushed back the piston and the rotor then spun freely. So seems like that would rule out the wheel lugs.

I guess I'll buy a new hose and see if that solves it.

Wed Jan 28, 2015 5:34 am

Try a new hose for sure.

Remember, stainless steel hoses are only Rubber hises with a braided stainkess civer on them.
They look pretty, they protect the hose but inside? Still rubber, possibly even rubber of questionable quality?

Dave

Wed Jan 28, 2015 5:52 am

If the pads are not retracting, that is the issue.

Remove the caliper, blow the piston out with air, look behind where the piston would seat in the caliper...full of junk? Clean, replace piston, lube caliper, reinstall caliper.

Make sure that ALL brake parts are properly installed and torqued.

Wed Jan 28, 2015 5:52 am

Rebuild or replace (both at the same time) the caliper's.
Sounds like your mechanic forgot to tell you that the one dragging isn't returning on it's own.
Remember--do both of them--not just the one dragging.

Wed Jan 28, 2015 7:02 am

Hi Terry!

The calipers are both new (rebuilt).

I'll try a new hose and cleaning out the caliper on that side.

Wed Jan 28, 2015 7:11 am

Switch front wheel to rear, i think your pulsing is now wheel or bad tire & will follow to rear, now pulling hand brake will show up. A bad rotor will cause a uneven wear pattern in tire, this will stay with tire as no one trues tires now, all caring govt says so. A bent wheel causes same, my 2cts.

Wed Jan 28, 2015 7:20 am

thanks Morymob.
I'll fix the caliper first and then check that out. the wheel and tire have been balanced (I watched them do it and used to do my own at a friend's shop)
the caliper is for sure sticking, and unless there's something about an out of true tire or wheel that would cause that to stick, I need to fix that anyway.

Wed Jan 28, 2015 7:58 am

If your calipers were rebuilt units, it might make sense to inspect the slider bores. I once attempted to install rebuilt units on a Syncro, and found that the slider bores were filled with blast beads, which prevented proper slide function

Wed Jan 28, 2015 8:43 am

An easy test of a clogged hydraulic system is to crack open the bleeder valve of the dragging wheel. If the wheel frees up with only cracking the bleeder you have a restriction before the caliper.

The stainless lines I use on the race cars have Teflon liners not rubber.

Wed Jan 28, 2015 8:57 am

rsxsr wrote:

The stainless lines I use on the race cars have Teflon liners not rubber.

Yup, the good ones do.

As far as "rebuilt" goes...first thing I do is thoroughly inspect every inch of the product before mounting anything.
Mount it, use it...you will be keeping it, even if the rebuild was crap.
Read most vendor disclaimers.

As stated earlier, compressed air will allow easy tests/inspections of calipers on a bench.

Wed Jan 28, 2015 9:28 am

Thank you, rsxr. Once again I was beginning to think the only Sambatista diagnostic step ever allowed was parts replacement. Just make a list of every part it could be and put in new ones until it is fixed. If that doesn't fix it start back at the top of the list and replace them all again cause you must have got a bad one.

If you think a caliper is dragging because pressure is remaining in it when there shouldn't be any, LET THE PRESSURE OUT! If that stops the dragging then you can assume that residual internal pressure is likely to blame. While the bleeder is open, let it drain some. If the line is fully clear it should gravity bleed easily.

Mark

rsxsr wrote: An easy test of a clogged hydraulic system is to crack open the bleeder valve of the dragging wheel. If the wheel frees up with only cracking the bleeder you have a restriction before the caliper....

Wed Jan 28, 2015 9:42 am

crazyvwvanman wrote: Thank you, rsxr. Once again I was beginning to think the only Sambatista diagnostic step ever allowed was parts replacement. Just make a list of every part it could be and put in new ones until it is fixed. If that doesn't fix it start back at the top of the list and replace them all again cause you must have got a bad one.

If you think a caliper is dragging because pressure is remaining in it when there shouldn't be any, LET THE PRESSURE OUT! If that stops the dragging then you can assume that residual internal pressure is likely to blame. While the bleeder is open, let it drain some. If the line is fully clear it should gravity bleed easily.

Mark

rsxsr wrote: An easy test of a clogged hydraulic system is to crack open the bleeder valve of the dragging wheel. If the wheel frees up with only cracking the bleeder you have a restriction before the caliper....

And just to add to this great advise, if you crack open the bleeder and the piston in the caliper does not retract (allowing the rotor to spin freely), then the problem lies in either piston/seal or the caliper slider area. In other words, if cracking the bleeder open does not free up the rotor, the problem is not going to be found anywhere else in the system but at the caliper. Unless of course you have multiple issues going on at once, but that is not likely.

Wed Jan 28, 2015 10:09 am

Thanks everyone. The collective knowledge and problem solving steps is as always much appreciated.

now to find a spot without a snowbank to jack up that side, remove the wheel and crack the bleeder...

insyncro sage advice on the part inspection. I'll for sure be inspecting in the future BEFORE installation.

Sun Apr 12, 2015 7:09 pm

Finally had a chance to look further into this.

I removed the left front wheel this afternoon, and then pulled the caliper. the lower guide pin seems to be the culprit. I pulled them to re-lube them and the upper one spins free by hand in the channel, but the lower one is catching on something when I try to turn it by hand, I have to imagine that this is the culprit, so I tried to hold it in a spot where it would slide easily.

I tried switching them and the other one wouldn't even slide in.

I didn't have a 22mm socket to remove the carrier to see what it looked like inside.

next step is for sure either replacement or removing the carrier for further investigation.

Sat Jun 20, 2015 7:52 pm

This issue continues.

I've taken the van to a VW specialty shop and they looked at it and gave it back to me and said they didn't know what was causing it. No change. They looked at the fronts and then on my way out the door said "maybe it's in the back, but we didn't look at that" so much for returning there, if they didn't look at the rears and I brought the van to them to suss out a braking issue?

After a 20minute drive through the city this evening, I decided to feel all the brakes.

Fronts felt hot, 1 second was all I could touch the edge of the rotor
rears were cold. One side was cold cold, like there had been almost no friction and the other was warm, but I could have kept my hand on it forever.

Now I know that the fronts take the lion's share of braking in most systems, but this seemed odd to me. I did install new drums this morning, but didn't change anything on the shoes, since I believe they are self adjusting.

I have two theories now:
1. For some reason the shoes are not self-adjusting correctly causing the rears to never really fully brake, this would cause the fronts to overheat and warp, giving me the pulsating pedal. Maybe the adjuster rods need to be cleaned or something else is binding in there. I have checked the ratchet springs and they are fine.

2. Proportioning valve has crap in it or is bad. Causing the rears to get little pressure while the front gets it all, again heating up and warping the rotors.

Would be happy to hear any theories on this.

Fri Aug 10, 2018 8:06 am

I'm dealing with dragging calipers too. Opening each caliper's bleeder allows the piston to retract. Rubber hoses are only 3 or 4 years old.

Is it likely that flushing the brake fluid would be enough to fix the issue or is this the lid to a can of worms?