Rear caliper hard-line nut, won't budge.

3826 Views 34 Replies 4 Participants Last post by SpiderWebb, Oct 16, 2007

SpiderWebb

Discussion Starter · Oct 7, 2007

Working on my '81 Spider rear-disc-caliper hard-line connector (nut), and it won't turn. The flat on the tubing-nut is being deformed, even though I am trying to be gentle, yet firm. Using, seemingly correct, 11mm combo wrench. Everything else sems to be losening up fine.

I have sprayed it with 'PB penetrating catalyst' and waited, repeat, repeat, tapped it gently, but it won't budge.

I even opened the bleeder valve to try and relieve pressure in the line while I tried to turn it. No go.

I'll try to bathe it in penetrating oil some more. I need to get the caliper off so I can install the new rotor (4 new drilled and slotted with pads and new front SS lines).

Any ideas, short of vice grips? I could go full-on-Ape and just turn the little bugger.

But I'm having an inner dialog to quell this option.

Is there a better brand penetrant? Are there replacement ends for hard lines? I've seen full hard lines for sale. But I'd like to get this finished by tomorrow. Thanks in advance.

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Gubi

· #2 · Oct 7, 2007

PB Blaster is the best penetrant I've used.

Shouldn't you be using a flare nut wrench on brake connections? If you're using a standard wrench that would probably explain the deforming.

SpiderWebb

Discussion Starter · #3 · Oct 7, 2007

Thanks Gubi

Thanks Gubi.

That would be it.

I'll get one tomorrow. I was not aware of the need. A nut is a nut is a nut in my book. Now I can get some sleep and get the proper tool tomorrow.

Flare nut wrench. I have a bunch of tools, including tubing tools for working on swamp-cooler copper tubing and such, but never heard of a 'flare nut wrench'. Would Sears have one? Auto Zone? Are they hard to find? What do they look like? I suppose they have a cupped end or something to support the outer shape of the nut for support. I guess I'll find out tomorrow.

Thanks for setting me straight.

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SpiderWebb

Discussion Starter · #4 · Oct 7, 2007

11mm Flare nut wrench.

Open just enough on one end to pass over the tubing, and grabs as much of the nut as possible. Thanks again Gubi.

I see said the blind man, and picked up his hammer and saw.

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Gubi

· #5 · Oct 7, 2007

I think I got mine from Sears, yeah. It's like a six-point box end, except it has an open slot to slip the brake line through. The idea is that it grips all sides of the relatively soft flare nut so as not to deform it.

I didn't know what one was until I started doing brake work. If it's a standard hard brake line with a long, sort of conical-shaped nut on it that's the tool you want.

Tifosi

· #6 · Oct 7, 2007 (Edited)

You might want to nab the 7/16" version of that wrench while you're at it.

Several of the hardlines use SAE instead of metric for whatever reason. The master cylinder has one on it for sure, and I'm not super positive, (it's been all summer since I touched mine there), but I 'think' the rear caliper lines you're working do too.

Anywho, 11mm and 7/16" are real close to each other size-wise and it may be that tiny difference one way or t'other you need to get a good bite.

Besides, full toolboxes are always cool.

Oh, and if you get a blank look from the store monkey when you say 'flare wrench', explain again but say 'line wrench'. (if they still look at you like you've got two heads, go elsewhere)

AlfaDuc

· #7 · Oct 7, 2007

You might also consider gently heating the nut with a propane torch to help break the fitting loose. All the obvious precautions apply when using a torch on the underside of the car, but I've been successful with this approach many times when all else failed. And if the fitting is a little messed up at this point, it might be a good idea to replace the line at this time (so that future work has a better starting point

).
Jim

SpiderWebb

Discussion Starter · #8 · Oct 7, 2007

Thanks for all the advice. I'm going to get new hardlines for the entire rear end. The 11mm flare nut wrench from Sears just 'spread apart' and the flare nut is now really rounded. I wish I had seen the post about the 7/16" version before visiting Sears.

The rotor in question is so bad it is in two parts. I was able to get the caliper to move out of the way for this one because it only took a moment to remove the rotor outer portion (see photo). There is a great deal of line from the axle to the caliper, so when I moved the caliper over, the tubing needed only to bend slightly.

The flare nut has not budged at all, so the entire hydraulic brake system is still intact.

Now I'm struggling to remove the broken rotor base. There is nothing to grab, other than the studs. I suppose I should count my blessings here. Thats a pretty good thing to have to grab on to.

I have removed the 2 screws holding the rotor, mounted a wheel and tire and am now trying to rock the rotor base off. I love brakes.

This is not a solution for the other side. I need to do it properly.

Once again, thanks for all the advice.

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SpiderWebb

Discussion Starter · #9 · Oct 7, 2007

Just so you don't think too badly of me, I just bought the car. I didn't abuse the brakes, the PO did.

Tifosi

· #10 · Oct 7, 2007 (Edited)

Umm, studs are attached/part of the front rotor, not the rear. On the rear they are in the hub and pass freely through the rotor hat.

You do have the parking brake released also, right?

Remove the two screws as seen at approximately 9 and 3 o'clock in your photo (you did) then rotate the hub til the holes seen at 12 and 6 o'clock are at approximately 3 and 9 and using a flat screwdriver, back off the adjuster for the parking brake til the hub clears the p-brake shoes and comes off. (the holes are there so you can get at the adjuster)

Likely you'll have to give it a few whacks with a hammer also as it looks like you've got quite a grode buildup between the center hole of the hub and the axle stub that'll need breaking loose.

SpiderWebb

Discussion Starter · #11 · Oct 7, 2007

Thanks. I have so much to learn. Only drum brakes in the past and that was 25 years ago. TIME FLIES!

I'll do that. I have penetrant around the axle/hub intersection and have cleaned all the gunk I can get at with an exacto knife between the two parts.

Parking brake is released.

Lunch, and then I'm back at it.

Tifosi

· #12 · Oct 7, 2007

Well, for all intents and purposes, once the caliper is out of the way you are working with drum brakes as that's how the p-brake is set up in there.

SpiderWebb

Discussion Starter · #13 · Oct 7, 2007

Hub turns now. Backed off the adjuster a wee bit. Still nothing to grab on to the drum part with.

It looks like a teeny drum brake system now with the outer rotor part gone.

The only thing holding the drum section in place now must be the scum around the axle and studs.

Penetrant, cleaning and...

Hammer time! Dah dah dah dah, dah dum, dah dum!

(tap tap, not bang bang)

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Tifosi

· #14 · Oct 7, 2007

As the rotor is a wash anyway, if you get truly desperate, you 'could' cut the drum into pieces.

Though it should lever off at some point (it might pull the shoes off with it, but it will come off.....)

SpiderWebb

Discussion Starter · #15 · Oct 8, 2007

Success!

Success! After much tapping, penetrant, wiggling, evil-eye, it came off with a single minor tap. It was the rust and gunk on the axle. Thanks for the help.

All is well now. I wish I could buy you all a beer.

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4

SpiderWebb

Discussion Starter · #16 · Oct 8, 2007

Both rears are done. Whew...
.

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2

Tifosi

· #17 · Oct 8, 2007

Cool, glad to be of use.

Did you set the p-brake shoes like you would conventional drum brakes with a very slight amount of drag?

Did you put the rotors on facing the correct direction? (I can't recall right off which way is which side, but it does make a difference AFA the slots are concerned)

Did you check/adjust the index of the caliper pistons? (link to IAP instructions and DL-able templates)

SpiderWebb

Discussion Starter · #18 · Oct 8, 2007

Did you set the p-brake shoes like you would conventional drum brakes with a very slight amount of drag?
Yes. Hate the shh shh shh sound, but, you know...

Did you put the rotors on facing the correct direction? (I can't recall right off which way is which side, but it does make a difference AFA the slots are concerned)
Yes, as per the papers that came with them. In the photo, that is the right rear wheel. So... it would spin clockwise in the photo for forward motion, making a nice spiral galaxy kind of motion. Opposite on the left.

Did you check/adjust the index of the caliper pistons? (link to IAP instructions and DL-able templates)
Yes. They did not need to be rotated. They seemed to be in the right angle inside after compressing them prior to installing the pads.

Hey, just a curious note, the pads just float in the caliper, pressed on the metal backing side of the pad by the piston. The pads are only held in position by the two pins and pressure from the caliper against the rotor.

How does it seat itself? Is it just ground into a force-fit over time? I also understand the glue used to hold the pads on the metal backing need to be heated and cooled for a while until the chemicals in the pad equalize, so called break-in period, and they will smell a bit.

Why don't the pads just rattle around in there. I suppose it's the pistons maintaining constant pressure.

Thanks for the help. Off work tomorrow, so I'll attack the fronts. Wheeee...

Here's a beer for all the help.
.

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Tifosi

· #19 · Oct 8, 2007

Robert Webb said:
Hey, just a curious note, the pads just float in the caliper, pressed on the metal backing side of the pad by the piston. The pads are only held in position by the two pins and pressure from the caliper against the rotor.

Correct. They just kinda dangle there like what's found on a modern motorcycle.

How does it seat itself? Is it just ground into a force-fit over time? I also understand the glue used to hold the pads on the metal backing need to be heated and cooled for a while until the chemicals in the pad equalize, so called break-in period, and they will smell a bit.

As they bed in, the wrinkly goo on the backs of the pads cooks a bit and kinds sticks the pads to the pistion.

If that's not present (super cheap pads won't have it) then they'll either rattle or squeal and likely need gluing in place by some of the off the shelf brake pad 'anti-rattle glue found at most parts stores. (there's also shims if the clearance is really big)

The rubber dust boot on the caliper piston helps a bit too as it kinda rolls over the edge of the piston when the pads are new and the pistons are fully compressed back. The roll sorta bumps against the back of the pad and damps vibration. (eventually they may even stick to the bonding agent on the back of the pads which makes for an exciting pad swap)

Why don't the pads just rattle around in there. I suppose it's the pistons maintaining constant pressure.

But the pistons don't maintain constant pressure.

Once you release the brake, pressure comes off, and any out or round irregularity of the rotor pushes the pads even further away.

Even a super duper bleed job can do it as the pistons retract with the fluid doing it's back-flow thing when you come up off the pedal.

The pads either stick to the piston and get pulled back with it, or they rattle. :shrug: (the rattle isn't always audible, but over time it is likely to start squealing due to glaze buildup)

Here's a beer for all the help.

Hey, I've drunk those before, thanks

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Tifosi

· #20 · Oct 8, 2007

Robert Webb said:
I see said the blind man, and picked up his hammer and saw.

Just then a bicycle pulled up to the kerb and 14 people got out, but do tell, how many pancakes does it take to shingle a doghouse on the second Tuesday of next week?

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