M1009 Brake Caliper Problems

[cucvrus]

If you grind the offending finger (Your reference)down on the backing plate. When you hit the brakes the backing plate and caliper will just spin around in a circle and tear the brake hoses. You will not be stopping. Do you have the backing plates switched right for left and vise versa? I am not looking at your truck or my truck but it seems you have something not copacetic. Check it close. These are the brakes. Do NOT go modifying the brakes. They seem to have worked well for 100K why put them in question now? Good Luck and take your time and do it right.

 

[Brogman]

If you did what I did you have to swap them out. They are on the wrong axle side. That will fix the problem. Yes it's a pain but much easier since you just had them apart. Just roll up you sleeves and do it. It will go quicker than you think.

 

[vtwinpilot]

Ok, makes sense, figured as much, Just pissed it looks like I have to tear both side's apart now. No idea how the backing plate got reversed, was prior to me owning it. Only other answer is wrong calipers, all numbers jive, just wish I would have gone back and retrieved my cores as those worked. So somehow there must be cores that function unless those were modified also, will never know now.

 

[vtwinpilot]

Is it on the backing plate? or was the "finger" on the caliper, I am suspecting a military mechanic modified the calipers otherwise they would not have worked.

 

[doghead]

post a picture

 

[vtwinpilot]

Will do, took a look at the calipers, both have a mark in the fresh paint on the same flange. Forgot to take a picture, won't be around it anymore today. Wear spot is quarter inch on each side. I had tried the passenger side so both are nicked the same way. Really glad I ran across this thread or I may have been held up for awhile.

 

[Brogman]

Believe me everything looks normal except the calipers with pads installed won't fit. You can get the calipers on with no pads but the finger you are talking about is under the caliper. Don't try to mod this it wouldn't be safe. While you have it apart get new seals and repack your bearings. It will be a day of work but it's worth it. You could drop the differential and replace the inner seals too while apart. Be careful tightening the spindle nuts they can strip.

 

[vtwinpilot]

The wear mark shows contact with backing plate.

 

[vtwinpilot]

last of the pics

You can see the contact spot just to the left where the knob sticks out. I still have a hard time understanding how backing plates could have been switched. The original calipers either were ground off or did not have such a large knob.

 

[cucvrus]

View attachment 652280View attachment 652281View attachment 652282View attachment 652283View attachment 652284You can see the contact spot just to the left where the knob sticks out. I still have a hard time understanding how backing plates could have been switched. The original calipers either were ground off or did not have such a large knob.

So is the moral of the story that the backing plates were switched and on opposite sides? Strange story. I can't imagine someone grinding calipers to fit. Did you service the spindle bearings while you had this truck apart?

 

[vtwinpilot]

I replaced a worn rotor on the drivers side, passenger is fine, drivers side inner shoe wore out. Bearings were good, replaced an inner seal that was showing slight wear to the rubber. Did not do anything to passenger side but pull off caliper. My mistake was to take them back for the core right away. Having a tough time with getting parts, out-of stock, have to order (ordered a hydro-boost,) credit card was double billed-caught it fixed that, needed the caliper credit off my card. Biggest hold up is my schedule is only allowing me an hour a day during the work week to pluck away at it. So the idea that the backing plates were switched came from previous poster on this thread that did that. They also took the cores back too soon.

 

[vtwinpilot]

Issue resolved, see last post, thanks folks

 

[cucvrus]

I will take pictures of core M1009 calipers for you. I will take a picture of each one if that helps.

 

[cucvrus]

and if it's an MV the confusion magnifies.

You are the one creating the confusion. This vehicle is nothing special. It is a 1984 Chevrolet K5 Blazer. The fact that it was built for the military is about the same as it being built for the power company. Being a standard production line vehicle with a special electrical system and special paint are about the only thing that separate it from the civilian counter part K5 Blazer. The brakes and driveline are the same thing. The engine is the same as a K30 engine and the other little parts that are bolt on(brush guard, shackles and rifle racks to mention a few) and can be deleted and the truck is back to the basic K5 Blazer. Do NOT even say it is anything more than a 1984 Chevrolet K5 Blazer when ordering parts. It just adds to the confusion like you said. Dual alternator trucks are still available to purchase and that does not change anything but the fans belts it requires. Auto stores do NOT list dual alternator parts to my knowledge. But be that as it may I will take some pictures today and post them of the calipers and backing plates for the M1009.

 

[cucvrus]

I took the time to show you how the calipers fit the backing plate. this is left side. Drivers side. Note the notch on the caliper will NOT fit in the backing Plate. And to grind it off will not change the fit. The backing plates are not interchangeable. I think we all learned that. The notch on the bottom of the axle housing knuckle is where the backing plate notch fits in place. Pictured 2 rights and 1 left in that order. I am trying to be helpful. This will cover the left side. I will post pictures of the right side. Next post.

 

[cucvrus]

Right side same deal. I used some HMMWV starter bolts as I was out of caliper bolts to use. But you can see the fit and placement.

 

[vtwinpilot]

sorry double post

 

[vtwinpilot]

Issue resolved, see last post......thanks folk's.....

 

[Recovry4x4]

That should put this all to rest. Rick, thanks for the extra effort to teach folks.

 

[vtwinpilot]

Now it is, Thank's for all the help pic's and input. Fixed the issue today, took ten minutes. A bit of extra sleep and being away from it for a few day's helped. Almost convinced backing plates were backwards after looking it over for a bit. Issue was one of those things that when you realized it you have to laugh. My hang up was not taking the collars for the mounting bolt's completely out, alway's thought I had them parked back far enough to clear. Today I slid them out, calipers dropped in place, slid collars in place, then bolts, snugged down, both sides are done, now just hook up line's. Then on to the hydro boost.