Better Rear Calipers Suggestion Needed

[MazdaSpeeder]

So, I have a failing rear caliper, and I am tired of the stupid allen screw adjustment. It has given me nothing but problems (already had to replace one caliper because of it and have stripped or nearly stripped a few) and I really would like to replace them with calipers that are retracted the good old fashioned way, with a C-clamp. I know the MSP calipers do this, but I'm not really looking to upgrade right now and replace my rotors too. So, really what I want is direct replacement p5 calipers that retract via a c-clamp rather than an allen screw. Does anyone know if such a thing exists?

 

[bigpturgeon]

+1

 

[destineal]

I think the msp rears have to be turned to retract

 

[MazdaSpeeder]

Now that you mention it, I think you are right. But this is still better than the allen screw. What about 626 calipers? Maybe they fit a P5 disc but retract a different way?

 

[gswift]

P5 rear calipers are fine, I service mine everytime I switch between summer & winter tires. I think the issue is ppl using the wrong lube for the slider pins, I've never had any issue!

 

[pcb]

The issue with our rear calipers is that Mazda chose a somewhat original approach to tying the P-Brake system together with the regular hydraulic brake system.

Every car company seems to do this in a different way. Usually it's the rear brakes that have the P-Brake applied to them. But they all have some kind of trick or technique involved in retracting them,... some need to have the piston rotated, some need to have a screwdriver inserted to rotate a toothed gear, some need a special tool.
Normally our rear calipers only need to have the allen screw turned then adjusted when new pads are installed. If the allen screw needs to be adjusted frequently because of too much movement in the P-Brake, then the internal self adjusting mechanism has failed.

The calipers need to adjust the mechanical movement to allow for brake wear and some brake cable stretch.

Being as our calipers have such a rare internal mechanism, we have to pay quite a bit for them and there is no kit that I am aware of to replace the internal components.

This is what our rear caliper mechanism looks like,... 90% of which is for the self adjusting the P-Brake.

 

[gswift]

^^this is correct however any of the seized rear calipers that I've pulled apart, corroded slide pins have been the cause of internal parts failing which leads me to believe that improper lube was used...

 

[pcb]

^^Agreed. I don't think it's the kind of lube so much, it's the fact that people generally don't bother greasing the sliders at all and only deal with their brakes when there is a problem,.. usually they're dragging and sometimes getting red hot.

I grease mine every year and I feel that's the bare minimum. I pack the boots full of grease and leave no air pockets for water to fill in.

I had a rear caliper replaced at the shop (before started doing my own work) and they didn't put any grease on the new caliper. When I checked the slider pins about 9 months later, there was only a thin film of factory grease on the sliders and they were already starting to rust.

There is also a seal at the P-Brake attachment pivot point which has a tendency to fail and let water into the mechanism rusting is and causing failure.

 

[rit14623]

What kind of grease, brand/name, do you guys use? I replaced the front and rear calipers and they were packed with a white-looking grease.

 

[pcb]

I personally use anti-seize, however that is probably not recommended because it's pretty thick,... kinda like a paste which can prevent the sliders from moving as freely as they should.

I like it because it stays put and I coat the boot ends liberally to help seal them up on the pin and prevent water from getting in. It doesn't wash or run off nearly as much as other grease.

I do have some special synthetic caliper grease but I didn't like how the container had a puddle of oil in it from it separating in the container.


Another thing to consider when you grease your rear slider pins, is to disconnect the P-Brake cable from the caliper and raise the end of the cable up outside the wheel well. Then use a pin to poke a hole at the end of the boot near the lug then insert the extension tube from your PB Blaster and fill the boot up with oil and let it drain down the cable towards the other end under the stick shift. (be careful not to rip the boot because that will let water in,... a small pin hole will close itself back up pretty good.)
Our P-Brake cables love to sieze up causing the brakes to drag which wears out the pads and can warp the rotors.

 

[gswift]

What kind of grease, brand/name, do you guys use? I replaced the front and rear calipers and they were packed with a white-looking grease.

The only lube I will ever use on my brakes is Wurth SAbestos silicone lube...

 

[pcb]

^^Yea,.. I think I'll get the proper grease and do it right,... ordinary grease can eventually dissolve the rubber boots, swelling them and turning them into mush,... here's the FSM info. (but I still think the wrong grease is better than not greasing them.)

 

[MazdaSpeeder]

Thanks for the little aside on how you maintain your calipers, but I keep mine greased, they are not corroded and I still have this problem. I'm looking for a stock sized replacement that retracts another way. Since there seems to be none, I guess I will just have to upgrade to MSP calipers.

 

[Flav]

FYI the 626 rears do not fit. I tried that because I wanted to do a OEM big brake kit upgrade.

It was assumed that the 2000 Mazda 626 rears fit, I went out and bought the caliper, rotors and pads for a 2000 Mazda 626 and they never worked out. So now I'm sticking with the stock set.

 

[pcb]

Thanks for the little aside on how you maintain your calipers, but I keep mine greased, they are not corroded and I still have this problem. I'm looking for a stock sized replacement that retracts another way. Since there seems to be none, I guess I will just have to upgrade to MSP calipers.

Well,... getting back on topic,... I've read a bunch of threads on replacement rears and nothing appears to be easy. The issue is usually the attachment of the p-brake cable.
Brian MP5T mentioned swapping left and right calipers to get things to line up.

I'm not sure, but even the MSP upgrade may require new P-Brake cables as well.

Another issue with the bigger calipers was that they don't fit inside 15 inch rims and my winter wheels are 15's so the big brake kit won't work for me.

 

[Flav]

Well,... getting back on topic,... I've read a bunch of threads on replacement rears and nothing appears to be easy. The issue is usually the attachment of the p-brake cable.
Brian MP5T mentioned swapping left and right calipers to get things to line up.

I'm not sure, but even the MSP upgrade may require new P-Brake cables as well.

Another issue with the bigger calipers was that they don't fit inside 15 inch rims and my winter wheels are 15's so the big brake kit won't work for me.

My exact dilemma as well.
Also, if we're talking about upgrading the rears to a larger size... does it really matter on our car's? I get if you want to change out the calipers for a different system..but changing out the rears just to have larger rears seems a little..pointless? Most of the stopping power comes from the front's does it not..

 

[pcb]

Yea,.. but our rears are annoying, unreliable, fussy and expensive. If there was a direct caliper swap for our cars I'd do it, and I'd bet it would be cheaper too.

 

[MazdaSpeeder]

I don't really want to upgrade the rears for size, I just want to get rid of the stock P5 calipers. The 15in issue is not a problem for me...I don't do snow tires. I believe the MSPs are a direct drop in, but I haven't done a ton of research. I seem to remember someone saying they hook right up to the brake line and ebrake.

 

[Flav]

I don't really want to upgrade the rears for size, I just want to get rid of the stock P5 calipers. The 15in issue is not a problem for me...I don't do snow tires. I believe the MSPs are a direct drop in, but I haven't done a ton of research. I seem to remember someone saying they hook right up to the brake line and ebrake.

From what I've read.. I'm about 80% positive they just hook right up. But don't they also have the set screw? Or are they done up differently from our cars?

 

[MazdaSpeeder]

Nope, they retract by rotating the piston with a special tool...or a wrench. I also believe they are self adjusting, so you don't have to turn the set screw back and get them just right. But I could be wrong about that. Someone with an MSP chime in.