Stubborn brake caliper bolt
 

It's me again...
Matt's '84 RX-7 is running like a top. Except for one thing: the right rear brake assembly began squealing/grinding last week. I jacked the car up, inspected the pads & rotor, and decided that they need to be replaced. No biggie, right? Well, I removed the lower bolt holding the caliper on, but the only tool that I could use on the upper bolt was an open-end or box-end wrench, and it was trying to round the points off the head. I've tried every tool I have (a goodly number to be sure) and I still haven't been able to budge the stubborn bolt. I even tried heating the metal that the bolt is threaded into with a torch, hoping to expand it enough to allow me to turn the bolt, but no luck. I'm about to the point of drilling-out and retapping the bolt -except that I can't get the drill onto it, because of the surrounding structure.

Any ideas out there? Do I have to drop the rear axle assembly to get access to the bolt head?

Kevin

I may be totally out to lunch on this one but on my mothers 85 GSL-SE that I just did rear pads and rotors on the only bolt removed was the bottom one. Then I rotated the caliper up on the upper pin after removing the E-brake cable retaining bolt and the cable. I don't see any reason to mess with the upper pin. Once the caliper was rotated up I could remove the caliper from the upper pin by sliding it inboard.

Don

ddsmith is correct. The upper "bolt" you describe is really a pin! Don't try removing it! That pin is most likely seized in the caliper housing. It happened to me. Pop the little cap off the back of the pin guide and soak the pin in a lot of penetrating oil. Get oil in there any way you can! I had to work mine with a lota oil and a lota muscle before it would even begin to move and swing freely. When you put the brakes back together be sure to lube that pin with synthetic grease or anti-seize or something. The caliper should be able to slide and move on the pin with ease.

Good luck!

Re: Stubborn brake caliper bolt
 

Ouch! Glad you didn't go that route.

The guys are right, it's a pivot only, no threads. You can use a large screwdriver between the rotor hub and the caliper to pry it back at the bottom, and it should rotate upwards easily. If not, then follow inittab's advice.

I thought I might add: inittab mentioned using anti-seize on the pin when you reinstall it. Anti-seize works great on lug nuts, spark plugs, and stationary bolts, but the caliper has to slide on the pivot, so anti-seize is no good. There are many good hi-temp greases; I use moly (molybdenum) on calipers and anything that is subjected to high heat but needs to be lubricated. Anti-seize will just thicken and lock your caliper in place.
You may well already know this (and inittab may have just misspoken about using anti-seize while making a valid point), but I thought it worth mentioning. :)

By the way, how did it go with the fuel pump? Did you have a chance to look into it further?

-John

FJ - ya know.... I've never actually used anti-seize on those pins but your probably right. Someone told me that they used it like that and that it works for them. Hmmmm..... Next time I see him I should probably beat him severely for that advise. ;) Personally I've only use a synthetic grease that's designed for brake parts.

Looks like a danged bolt to me...

...but I'll defer to your collective experience...that sucker is TIGHT! Using a crowbar, I've been able to move the bottom of the caliper about an inch. I soaked that turkey with penetrating oil before quitting last night, so I'll see if it made any difference when I get home this evening.

Once I get the caliper rotating freely, how do I remove the rotor? This brake ass'y is different from anything I've ever seen before...

Thanks for your advice, gents! This is my first Mazda experience, and I'm learning as fast as I can...

To FJ - I haven't had a chance to pursue the fuel-pump thing yet, due to the current crisis with the brakes. But I will. Someday.

Kevin

crowbar. Yup! sounds about right, that's what mine needed

remove the caliper bracket and the rotor should slide off.

If that caliper was *that* tight if I were you, I'd check all four calipers for similar problems.

I wouldn't go that far... :p:

I have a friend who used anti seize in the swing arm of his motorcycle years ago: it seized after a few months. No lubricating qualities at all.

kspaight: If the rotor does not want to come off easily, there are threaded holes in the rotor to help. Screw in a suitable size bolt, and it pushes against the hub behind, popping the rotor off. Good luck with the fuel pump, when the time comes. :)

-John.

Removing rear caliper
 

To make your life easier, it's best to remove the parking brake cable connection before trying to remove the rear caliper. Front caliper removal is MUCH easier as it doesn't have that complication.

Be sure to mark the bolt threads with chalk. Saves you the trial and error hassle of correct adjustment when you reconnect the brake cable.

:cool:

PS Buy yourself a real small pipe wrench for those extra stubborn bolts. Cut a piece of pipe to slide on the end for extra leverage. Works every time.

But, always spray on some Rust Knocker type oil and let soak a bit before your first tug on it.

Kevin,
I feel for you. Sounds like you've got one of those cars that has seen some bad weather. With the bottom bolt removed the caliper should rotate up using the upper pin as a pivot. Sounds to me that your upper pin was not lubricated and is seized up. Once you fight this battle your next one will be removing the two screws that hold the rotor to the hub. Phillips head screws and I would recommend impact wrench if they are real tight. There should be another hole that is threaded in between the two phillip head screw which is used to jack the rotor from the hub once the phillips screw are out and as mentioned earlier the right size bolt is installed. If this car has seen bad weather you'll definately need to use the jacking bolt for removal.

Don

You guys are great! With the help of my weightlifter/wrestler son and a crowbar, we were able to pivot the caliper up enough to remove the one remaining brake pad (did I mention that the inner pad FELL OUT when I removed the wheel?) and the rotor, which we replaced with new parts. The only real challenge there was screwing the caliper piston back into the cylinder without the magic Mazda tool. Once all was in place, I found I had good pedal, excellent stopping power, and no squealing. And the emergency brake will stop the car - eventually. Got some adjusting to do there...

Thanks again to all of you for your help. Matt and I are learning a lot, and hopefully can contribute to this group in our own little way in the future.

Kevin

"...The only real challenge there was screwing the caliper piston back into the cylinder without the magic Mazda tool...."

Try "Sears" they have a little cube thing that fits on to a 3/8" socket. On each side of the cube is a set of pins for different types of breaks and one side fits the RX7 pretty well.

Doing the break pads was one of the first jobs i did on my '83 and it took me about 5 hours to do the first one and about 20 minutes to do the last so once you learn it does get easier!

you might also want to invest the $80 or so in the shop guide for your year. the pictures stink but it does remind you about things like removing the hand break cable and how to adjust your hand break when you are done.

good luck and have fun!

-phil

Thanks for the suggestion, Phil - I'll check with Sears this weekend...

I'll let my son buy the shop manual - it's his car, and he's gonna be the one doing most of the work...

...y'all believe that, dontcha? ;-)

Cool tool from sears.com...


Lisle Disc Brake Piston Tool
$11.99

Sears Item #00946344000
Mfr. Model #28600