Hey, first time posting.

Just bought a 2000 Chevy Blazer LT 4x4. Was sitting for a bit am im trying to restore it. 180,000km

Im trying to go over this truck with my limited knowledge to decide if I want to keep them or not. The blazer has both rear caliper seized and the coolant is red, murky and there is a lot of grit in the coolant reservoir tank. The oil cap and dipstick look normal, no chocolate milkshake. The rad is clean, no dried up white crusty substances. Besides a coolant flush is this something I should be worried about?

See pic


Will be taking off rear tires and playing w brakes and bleeding ( ive read about the ABS module issue ) right after i post this.

 

Unfortunately, that's pretty typical of old DexCool antifreeze... Run a flush solvent in it for a bit, drain and refill with just water, run for a bit, drain and refill again with water, run for a bit, then drain that and fill with either DexCool or traditional green antifreeze. This should loosen up and get all the old junk out of the system.


Do NOT switch to the green antifreeze without thoroughly flushing out the old DexCool from the system, you'll have all kinds of issues... But so long as all the old DexCool is flushed out, it's perfectly safe to switch to the green stuff. It's on my agenda for the next time I have to open up my cooling system for any reason...

 

These are notorious for the rear calipers seizing. Just get a set calipers with brackets and replace them. They are aluminum and they don't last long and once they are stuck they are pretty much done for. If you are good with coupon codes you can get a set for less than $100 after core return at Advance auto. I would not suggest getting them without the brackets. As far as the coolant, I agree with blazen_red_4x4 on that.

 

In days of old when I was in school and broke all the time, we used to successfully rebuild calipers with new seals and on ocassion, a new piston. In modern times, I stopped doing this because I had so many problems with seized pistons after the rebuilds. I don’t know if it’s crappy pistons that warp or seals that bind but I got tired of trying to figure it out and now I just put in rebuilt calipers on all brake jobs with lifetime warranty rebuilds. That not a perfect choice either because sometimes the rebuilds have problems and need some persuasion before installation. Another thing I have learned is to anneal the copper washers before the install by heating them to red hot with a propane torch. That softens them up and gets my seal rate to 100% vs making a mess unbolting and rotating washers until the banjo bolt seals the hose block. Either these washers are less precise or harder than those same “good old days”, or the rebuild sealing surfaces are a challenge but this fixes that problem. Also, never throw out old copper washers. Anneal them and sand them flat and you can save your **** at 9pm on a Sunday when your wife leaves for work at 7am the next morning and you want to maintain your perfect record (or for single guys you don’t want endless abuse from your buddies).

George

 

@GeorgeLG

We've ran into the same problem with more modern calipers being rebuilt.
The clearances are much tighter, seals sometimes harder. Just a little scratch can make them either leak or seize.

If I can get them below 150$ I'll buy reman from a known good source. Else I try to have them properly honed, because I think that this is one of the major problems when the cylinders still retain some form of ridge from corrosion.

I'll have to rebuild a set for my Blazer this winter, but the 94 has the sturdy old ones, and I'm starting from a set of good calipers.

 

I have been looking at flushing and putting in the organic yellow OAT, myself.

 

Im working on the brakes now, and the rear drivers side was not moving freely when jacked up in the air. Took a bit of pulling to spin the tire. Anyway, took the tire off, took the caliper off and saw the inside brake pad was worn to the rivets. completely shredded the inside of the rotor lol.. anyway, im trying to test the health of the caliper and the pins move freely, and the piston moves back and forth when i put a c clamp on it and compress it or push the brake pedal to push it out. Not sure what locked up and completely shredded the inside pad/rotor.

The passenger rear has a seized pin, but the pads and rotor survived. piston is able to compress and comes back out when brakes applied. tire also wouldnt move freely.



front drivers tire wouldnt spin as freely as it should, but not as stuck as the rear two. Brake pads are good, rotor is good, and caliper pins move freely and both pistons compress and return to position.

When the brake lines are hooked up and c clamp is put on the piston, would a healthy piston compress 1/8" and then when c clamp is released return to previous position? How do I test my brake pistons?

 

Those calipers and slide pins aren't really serviceable unless you are good are rebuilding calipers. As cheap as they are, I just replace them.

 

Ok so replaced rear rotors, calipers, pads, and bleed the brakes etc. Brakes feel ok, pedal is firm at the bottom, might need to go see the dealer to perform the ABS flush for the brake lines one day...

All 4 tires are now rotating freely thx for the help. Also i topped off the coolant with de ionized water and will keep an eye on it.