stuck caliper...

jim beam wrote:
> there is
> actually a strong argument for slipping the clutch more than might be
> assumed from reading so far in this thread. the purpose of the clutch
> is to allow both drive-away & smooth shifts. it's entirely feasible to
> shift no clutch, but it's hard on the vehicle - motor mounts,
> transmission, diff pinions, drive shafts, even the clutch plate torque
> springs. harsh shifting causes much greater momentary spike loads in
> all these components than does shifting smoothly & using a bit of
> clutch.

An excellent reminder of the reason for a clutch. I've always believed
in moderation--it helps both the body and the machinery last longer.
Balance is key to longevity.

TeGGer® wrote:
> Driving environment helps too. My driving is mostly highway, so the clutch
> gets little use until I've left the highway.

Ahh. I live in NYC, and on a hill to boot. While most of my driving is
outside of the city, there's a fair bit of time spent getting out or
back in. I don't expect my clutch to last as long as yours, for sure,
even if I had had it from the beginning.

> What you're trying for when you do use the clutch is to use it sparingly
> and with minimal slip. You want the quickest, smoothest engagement possible
> with the least slip you can achieve. When you're stopped at a light, the
> shifter is in neutral and your foot is OFF the pedal.

That is precisely what I do.

> If you're timing your shifts right, there will be essentially zero wear on
> the clutch when the car is moving. The only wear will occur when you're
> actually getting the car started from rest. Keep that wear down and the
> clutch will last ages.

Ahh, parallel parking on a hill--that may be my clutch's downfall. But I
do my best to get it right the first time.

> He was one of those people who used the clutch to hold the car
> still on inclines, letting the car roll back, then blipping the clutch to
> bring it forwards again, roll back, blip forwards, etc, etc, etc. Yeesh.

Yeah, what an idiot. World is full of people who don't have any idea how
equipment works and a sense of making it last.

I do a fair bit of computer consulting. Recently did a job for a client
out in NJ, and noticed on my way out at about 10 p.m. that her neighbor,
who was running a computer learning center for kids, had a whole bunch
of nice flat panel displays on full, no screen saver. So I suggested to
my client that she might mention to her neighbor that if she wanted to
make them last she should enable the power saving mode.

Got a call from the neighbor and she wanted to know if she really had to
do that given that she was just going to get new ones in 30 months...
some people...

TeGGer® wrote:
> Driving environment helps too. My driving is mostly highway, so the clutch
> gets little use until I've left the highway.

Ahh. I live in NYC, and on a hill to boot. While most of my driving is
outside of the city, there's a fair bit of time spent getting out or
back in. I don't expect my clutch to last as long as yours, for sure,
even if I had had it from the beginning.

> What you're trying for when you do use the clutch is to use it sparingly
> and with minimal slip. You want the quickest, smoothest engagement possible
> with the least slip you can achieve. When you're stopped at a light, the
> shifter is in neutral and your foot is OFF the pedal.

That is precisely what I do.

> If you're timing your shifts right, there will be essentially zero wear on
> the clutch when the car is moving. The only wear will occur when you're
> actually getting the car started from rest. Keep that wear down and the
> clutch will last ages.

Ahh, parallel parking on a hill--that may be my clutch's downfall. But I
do my best to get it right the first time.

> He was one of those people who used the clutch to hold the car
> still on inclines, letting the car roll back, then blipping the clutch to
> bring it forwards again, roll back, blip forwards, etc, etc, etc. Yeesh.

Yeah, what an idiot. World is full of people who don't have any idea how
equipment works and a sense of making it last.

I do a fair bit of computer consulting. Recently did a job for a client
out in NJ, and noticed on my way out at about 10 p.m. that her neighbor,
who was running a computer learning center for kids, had a whole bunch
of nice flat panel displays on full, no screen saver. So I suggested to
my client that she might mention to her neighbor that if she wanted to
make them last she should enable the power saving mode.

Got a call from the neighbor and she wanted to know if she really had to
do that given that she was just going to get new ones in 30 months...
some people...

Abeness wrote:
> jim beam wrote:
>
>> clutch wear comes from drive-away from a standstill, holding it on the
>> clutch on hills, "resting" a foot on the clutch pedal on the freeway,
>> etc.
>
>
> And from dropping into a lower gear at high speed without rev-matching.
> If I'm going, say, 40 and drop into second gear, the revs are going to
> shoot up to 4K or more. If the engine is at ~1K or 1.5K after
> disengaging the clutch, there will be clutch wear during engagement in
> second.
>
> I don't do such extreme shifts very frequently, but perhaps I'll pay
> more attention to rev matching and doing things more smoothly. I just
> don't especially like the idea of revving to high rpms during
> downshifting, as I'm so used to letting my foot off the gas during a shift.

drive a big rig. there, high revs are your friend - you'll /never/
succeed in getting a downshift without them. 4krpm is on a honda is
nothing. if you need comparision, f1 car's don't even idle below 3k.

Abeness wrote:
> jim beam wrote:
>
>> clutch wear comes from drive-away from a standstill, holding it on the
>> clutch on hills, "resting" a foot on the clutch pedal on the freeway,
>> etc.
>
>
> And from dropping into a lower gear at high speed without rev-matching.
> If I'm going, say, 40 and drop into second gear, the revs are going to
> shoot up to 4K or more. If the engine is at ~1K or 1.5K after
> disengaging the clutch, there will be clutch wear during engagement in
> second.
>
> I don't do such extreme shifts very frequently, but perhaps I'll pay
> more attention to rev matching and doing things more smoothly. I just
> don't especially like the idea of revving to high rpms during
> downshifting, as I'm so used to letting my foot off the gas during a shift.

drive a big rig. there, high revs are your friend - you'll /never/
succeed in getting a downshift without them. 4krpm is on a honda is
nothing. if you need comparision, f1 car's don't even idle below 3k.

Abeness wrote:
> jim beam wrote:
>
>>>> the thrust bearing should last at least the life of the clutch. if a
>>>> clutch is badly adjusted
>
>
> Adjusting the clutch is just a matter of adjusting it at the pedal as
> described in the Helm manual, right? I'm due to do that shortly, when I
> replace the clutch master cylinder.

if it's hydraulic, it's self adjusting at the slave end, and all the
pedal end does is adjust the gap between the pedal rest stop and the
cylinder engagement point. yes, adjust per the manual, if required.
unless stuff's worn & has been messed with, there's little if anything
you'll need to adjust.

>
>> if the flywheel is skimmed, the bolt mounting surface needs to be
>> skimmed also to maintain the same degree if differential with the
>> friction surface that it had when new. frequently, that's not done so
>> people wonder why the clutch goes again so soon again after...
>> insufficient pressure can be brought by the pressure plate.
>
>
> An excellent tidbit, thanks. Lord knows what was done on my car when the
> previous owner had the clutch replaced. Here's to hoping they were a
> savvy shop...
>
>> crawling inside the hopper with an air hammer to remove all that
>> concrete is something else.
>
>
> LOL!!

Abeness wrote:
> jim beam wrote:
>
>>>> the thrust bearing should last at least the life of the clutch. if a
>>>> clutch is badly adjusted
>
>
> Adjusting the clutch is just a matter of adjusting it at the pedal as
> described in the Helm manual, right? I'm due to do that shortly, when I
> replace the clutch master cylinder.

if it's hydraulic, it's self adjusting at the slave end, and all the
pedal end does is adjust the gap between the pedal rest stop and the
cylinder engagement point. yes, adjust per the manual, if required.
unless stuff's worn & has been messed with, there's little if anything
you'll need to adjust.

>
>> if the flywheel is skimmed, the bolt mounting surface needs to be
>> skimmed also to maintain the same degree if differential with the
>> friction surface that it had when new. frequently, that's not done so
>> people wonder why the clutch goes again so soon again after...
>> insufficient pressure can be brought by the pressure plate.
>
>
> An excellent tidbit, thanks. Lord knows what was done on my car when the
> previous owner had the clutch replaced. Here's to hoping they were a
> savvy shop...
>
>> crawling inside the hopper with an air hammer to remove all that
>> concrete is something else.
>
>
> LOL!!

Abeness wrote:
> TeGGer® wrote:
>
>> Copper grease or M77 , not silicone, goes there. Check my Brake
>> Service pages again for photos of where to put the grease.
>
>
> Couldn't find copper grease. I wound up just using a dab of the CRC
> brake caliper grease on the edges of the pad backing plate, where it
> sits in the stainless mounting clips, and around the edge of the piston
> where it hits the shim.
>
>> Rubber should be fine. It lasts a long time. If it is aged and
>> brittle, you'll know the instant you try to pull it out of the groove.
>
>
> The rubber is indeed fine. Aging, yes, but still supple enough that I
> was able to pull it back and apply a bit of brake fluid in the pinch--I
> couldn't find silicone grease by the time I had to do the job, ad it
> appears that my pistons are starting to rust in the boot groove. I
> scraped out a bit of it, but I'll either have to pull the pistons out,
> sand, and replace, applying silicone grease then, or replace the
> calipers when they seize. I did not see rust further in than the groove,
> but that's of course only a matter of time unless I stop it.
>
> At the moment I can't decide which would be easier--probably just doing
> the piston, unless the bore is rusted, too, so maybe wholesale
> replacement is in order. Probably no way to know how long I can wait,
> but perhaps it will be a project for next summer. Suppose I could check
> the fluid in the spring to see how dirty it is, and just change it more
> frequently if necessary, for a while.
>
>> It's hard to turn because it's so big and may be gummed up, but you
>> CAN turn it. Put silicone in first, work the piston in and out a few
>> times to loosen it up, then try to turn it. You need to eject it
>> enough to pull the dust boot off the groove in the piston. Make sure
>> you don't scar up the piston inboard of the boot groove.
>
>
> In fact I was able to turn it by grabbing the edge firmly with a pliers
> and turning it. Did take a good deal of effort, but I was able to turn
> it about halfway around to get at the groove rust I mentioned.
>
> The upshot is... the piston wasn't stuck, and the pins are fine (I did
> apply more grease while there). Must have been rust sticking the pad
> edges in place--it was pretty firmly stuck there, I did have to use a
> screwdriver to pry it out. The rear pins are starting to bind a tad on
> the left (only one I had time to check), and since the pins are fine I
> assume it has to be the bore. See below.
>
> I took a bunch of rust out, but foolishly didn't think to apply grease
> between the stainless clips and the caliper tabs they abut--i.e., on the
> other side of the stainless lip from the pad backing plate edge. Ahh
> well. I'll keep an eye on it. I do need a better way to sand down those
> tabs. Perhaps a wire brush drill attachment next time.
>
> Anyhow, got the pads replaced and the fluid changed. Boy, was it a nice
> coffee color--after pushing the problem caliper piston in with the
> clamp, the reservoir was swirling with rust, and the other lines were
> similar. Lord knows the last time it was changed, and I have to assume
> there's rust in the bore that will be a problem at some point.

more likely, all the goop got squeezed all the way up from the caliper.
whenever pushing a piston back in, /always/ open the bleed nipple and
disgard what gets squeezed out. it's always contaminated.

i recommend re-bleeding using full pedal travel to make sure you move as
much of that stuff back out of there as possible. full travel ensures
you really do press it out, not leave the cruddy stuff at the bottom of
the cylinder.

when you bleed, you may want to bleed at the caliper banjo bolt too.
avoid getting the muck back into the caliper!

>
> I also checked the left rear caliper, where the p-brake isn't working.
> Tried screwing the piston all the way in, and was also able to screw it
> out (not all the way, of coures). Applying the main brake pushed the
> piston out, and releasing the main brake allowed it to retract.
>
> Applying the p-brake did nothing, however--no piston movement, whether
> the piston was completely screwed in, or screwed out somewhat. I did not
> have time at that point to compare the action on the right side, but I
> presume it's supposed to push the piston out.

yes, it is suposed to push the piston out. the arm moves, right? if
not, check the brake cables. if it does, disconnect the brake cable and
see if it moves by hand. if it's all loose and bottoms out, sounds like
you may have a problem.

>
> What bothers me about this failure is that the rear calipers were
> supposedly replaced at 111,494. The local dealer noted that the p-brake
> "needed attention" when I had the car inspected prior to purchase at
> 113K, and there's no way a caliper should fail within 1600 miles. Damn.
> Why the bore would be rusted so fast, too, I dunno. I've contacted the
> previous owner to see if it's possible to pursue it, but it may not be,
> or be worth it--especially since she threw out the receipts when I
> bought it!! More and more I'm finding out why that was a terrible
> thing... hope there's no more. Sheesh.

if they were replaced, they should be peachy. if not, make sure you
familarize yourself with the parts drawings & tegger's removal
instructions. maybe yours got reassembled wrong, or the adjusting
screw's in need of a little encouragement to start doing its job.

>
> Many thanks for everyone's help here, especially you, Tegger. I've now
> done my first brake job, and am invincible!! <vbg> (actually wasn't hard
> at all; now, a timing belt I might leave to a shop)

Abeness wrote:
> TeGGer® wrote:
>
>> Copper grease or M77 , not silicone, goes there. Check my Brake
>> Service pages again for photos of where to put the grease.
>
>
> Couldn't find copper grease. I wound up just using a dab of the CRC
> brake caliper grease on the edges of the pad backing plate, where it
> sits in the stainless mounting clips, and around the edge of the piston
> where it hits the shim.
>
>> Rubber should be fine. It lasts a long time. If it is aged and
>> brittle, you'll know the instant you try to pull it out of the groove.
>
>
> The rubber is indeed fine. Aging, yes, but still supple enough that I
> was able to pull it back and apply a bit of brake fluid in the pinch--I
> couldn't find silicone grease by the time I had to do the job, ad it
> appears that my pistons are starting to rust in the boot groove. I
> scraped out a bit of it, but I'll either have to pull the pistons out,
> sand, and replace, applying silicone grease then, or replace the
> calipers when they seize. I did not see rust further in than the groove,
> but that's of course only a matter of time unless I stop it.
>
> At the moment I can't decide which would be easier--probably just doing
> the piston, unless the bore is rusted, too, so maybe wholesale
> replacement is in order. Probably no way to know how long I can wait,
> but perhaps it will be a project for next summer. Suppose I could check
> the fluid in the spring to see how dirty it is, and just change it more
> frequently if necessary, for a while.
>
>> It's hard to turn because it's so big and may be gummed up, but you
>> CAN turn it. Put silicone in first, work the piston in and out a few
>> times to loosen it up, then try to turn it. You need to eject it
>> enough to pull the dust boot off the groove in the piston. Make sure
>> you don't scar up the piston inboard of the boot groove.
>
>
> In fact I was able to turn it by grabbing the edge firmly with a pliers
> and turning it. Did take a good deal of effort, but I was able to turn
> it about halfway around to get at the groove rust I mentioned.
>
> The upshot is... the piston wasn't stuck, and the pins are fine (I did
> apply more grease while there). Must have been rust sticking the pad
> edges in place--it was pretty firmly stuck there, I did have to use a
> screwdriver to pry it out. The rear pins are starting to bind a tad on
> the left (only one I had time to check), and since the pins are fine I
> assume it has to be the bore. See below.
>
> I took a bunch of rust out, but foolishly didn't think to apply grease
> between the stainless clips and the caliper tabs they abut--i.e., on the
> other side of the stainless lip from the pad backing plate edge. Ahh
> well. I'll keep an eye on it.

jim beam wrote:
> drive a big rig. there, high revs are your friend - you'll /never/
> succeed in getting a downshift without them. 4krpm is on a honda is
> nothing. if you need comparision, f1 car's don't even idle below 3k.
>

Yeah, I suppose you're right--the tach is marked with red only at above
~7K rpm. I just get worried about that high-pitched engine buzz, bot
something I'm used to. But then I'm coming from a V8-350 (5.0 liter) on
a station wagon. That sucker probably never revved over 3K... And if it
did, the deep throaty roar just sounded normal. ;-)