19mm Caliper Bracket Removal

Jkb242

Original poster
Member
May 19, 2019
239
CLT
I need to replace the front rotors on the 2002 Envoy requiring removal of the rotor brackets and adjust the rear emergency brakes shoes on the rear so that’s 8 of the 19mm bolts I will need to remove and I’m big time stuck on the first bracket. NONE OF THE BOLTS ARE RUSTED, no salt and snow exposure ever. At my age, getting these loose just requires more power than I have given the right working area. I can’t fit my large impact driver I use for the lug nuts, I have sprayed WD40 on the first bolts to remove, still no luck. I’m using a 6 sided 19 mm 1/2” socket with breaker bar. Can anyone recommend another penetrant that might help. I have the rear jacked up on stands with the floor jack just in contact with the differential for safety but I just can’t seem find a way to get the torque I need to break them free. IAny suggestions that might help would be much appreciated.

Thanks!
 

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
They're 18mm and usually need a breaker bar to break free as they are torqued pretty heavy and have Loctite.

Regular WD40 is junk as a penetrant. PB Blaster is pretty good. Some also swear by tranny fluid and acetone.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
I had to turn the wheel so the leading edge of the caliper was pointed out, and was able to get a breaker bar on them.
 
  • Like
Reactions: BrianF and Mooseman

Jkb242

Original poster
Member
May 19, 2019
239
CLT
I need to replace the front rotors on the 2002 Envoy requiring removal of the rotor brackets and adjust the rear emergency brakes shoes on the rear so that’s 8 of the 19mm bolts I will need to remove and I’m big time stuck on the first bracket. NONE OF THE BOLTS ARE RUSTED, no salt and snow exposure ever. At my age, getting these loose just requires more power than I have given the right working area. I can’t fit my large impact driver I use for the lug nuts, I have sprayed WD40 on the first bolts to remove, still no luck. I’m using a 6 sided 19 mm 1/2” socket with breaker bar. Can anyone recommend another penetrant that might help. I have the rear jacked up on stands with the floor jack just in contact with the differential for safety but I just can’t seem find a way to get the torque I need to break them free. IAny suggestions that might help would be much appreciated.

Thanks!
Thanks Mooseman, always nice to get your input. Have applied PB blaster waiting overnight to try again. Hopefully this will help. Thanks for catching that goof on the wrong size socket but funny I never tried the 19mm, I knew it was 18mm but how I got that is beyond me.
 
Dec 5, 2011
574
Central Pennsylvania
I'm going to ask the stupid question.... are you turning them in the correct direction?
I don't think they're "left hand thread" and I don't remember if the heads are accessed from the back or the front, but I do remember they were a huge pain in the butt.
Breaker bar for the win... penetrating oil for the assist.
 

TollKeeper

Supporting Donor
Member
Dec 3, 2011
8,047
Brighton, CO
They are not left hand threaded. I also had to use a breaker bar, with a pipe on the end of that!
 
  • Like
Reactions: Redbeard and mrrsm

Mooseman

Moderator
Dec 4, 2011
25,262
Ottawa, ON
Yep, normal turn left hand turn to remove.
 

Redbeard

Member
Jan 26, 2013
3,466
To cheat a bit more while you apply pressure with a breaker bar tap the end of the breaker bar with a hammer (you effectively made a "home made" impact wrench). Also remember if the bolt you are fighting is on the other side of the caliper "righty tighty, lefty loosy" will be BACKWARDS from your point of view. As one faces the head of the bolt go with the old saying "righty tighty, lefty loosy". This is easy to confuse when the head of a bolt is on the back side of a part. Take your time making sure of the direction you want the bolt to turn is correct.
 
  • Like
Reactions: BrianF

Reprise

Lifetime VIP Donor
Supporting Donor
Member
Jul 22, 2015
2,724
PB Blaster is my definitely my penetrant of choice... but sometimes, only brute force will do.

If you have access to a propane torch (like the little Benz-O-Matics), you can apply heat to the bolt, and try and loosen it. Try and get it cherry hot, if you can. You can pick these up in a kit from your local hardware, etc., and replacement cylinders can be found anywhere - even at WalMart (they probably sell the kits, too).

I haven't seen a bolt on a GMT360 yet that I can't get off with a 1/2" breaker bar, if I can get access to the bolt. Sometimes I have to put a length of pipe over the bar, but the bolt comes off.

If your calipers have never been off, you'll find yellow thread sealant on the bolts. That's GM sealant, and it is pretty strong stuff. Not as bad as red, but it's close.

If none of that works, you mentioned an impact. If you have one, but it doesn't fit in the space, you can get wobble extensions in various lengths, swivel sockets, etc., that can help.

Depending on how heavy-duty your existing gun is, you can try and reverse direction -- after trying to loosen the bolt, reverse direction and give it a couple of shots. Back and forth a few times, and it should move, eventually.

Your location is listed as CLT, which I'll guess is Charlotte, NC, as that's the airport code. There are a ton of Harbor Freight locations in that metro area. You can get all of the extensions, sockets, etc., there, if you've never been to one. And their hand tools are guaranteed forever, no questions asked. I've never broken a socket of theirs (well, I did, once... using chromium sockets with an impact gun is asking for trouble)

Since these are the caliper bolts, that reminds me of what I use, especially for one of the two, as it's a bit obstructed.

I have a set of these (and I didn't have to pay $32 for them, either...sorry). The 18mm you need is in the set. I think you'll also need an extension - maybe a 3"-"6". But these work for me on calipers. Even the ones on my full-size pickup (the torque on those is spec'd at about 225 ft/lb, while yours is spec'd at about 168, IIRC - ?) You can use these with a breaker bar, too (by hand).


If you're *still* having trouble, HF also sells an electric impact gun that has nearly 1200 ft/lb of loosening torque. I have one, and it's a good tool. But it's a bit heavy, and bulky, too. Extensions are your friend, with this. Do not put a 4-way universal (even an impact-rated one) on the gun -- the torque will rip it right off as soon as you pull the trigger. The swivel impacts are fine.

Finally, if *none* of that works / suits you... take it to a shop and have them loosen the bolts with their pneumatic guns. They'll charge you a few bucks for the privilege.
 
  • Like
Reactions: Mooseman

Jkb242

Original poster
Member
May 19, 2019
239
CLT
Thanks for these tips. Because of the limited space/access and because I don’t have access to a lift, I’m not able to find many opportunities to get the swing a long breaker can provide. I am using pipe extensions for additional torque but.access is my worse challenge. PB blaster is soaking over night and I’ll have another go at this tomorrow, Friday. As for tool and HF, I was back there today searching for alternate solutions as mentioned. I have a warble extension and noted the socket was getting warm when lying under the car using the electric impact 1/2” driver so I’m loosing energy due to the heat. I have an extension that does not have the warble which I’ll try tomorrow. This impact driver will remove the lug nuts so was hoping it will work here. These are original brakes so are factory install unfortunately they are really tight.
Yes, I am not torquing the wrong direction but the idea of switching directions on alternate hits may be an idea as I have seen this used before.
Thanks to all, will post results. Maybe 25 years ago this would not have posed such a challenge for me at 74, I can usually handle these encounters but the limit on breaker bar and pipe multipliers are severely limiting. 😊
 

mrrsm

Lifetime VIP Donor
Supporting Donor
Member
Oct 22, 2015
7,642
Tampa Bay Area
What about using a "Force Multiplier" like THIS Device?

https://www.amazon.com/dp/B00GUOFDHA/?tag=gmtnation-20

FORCEMULTIPLIER.jpg

I have Two Versions of THIS "KLUTCH" Model-Design (3/8" and 1/2") that work very well. It provides a 3.4:1 Ratio of Mechanical Advantage:

AGOODFORCEMULTIPLIER.jpg

Also... Would the Vehicle be drive-able if you put it back down on the deck? If so... What about looking over your "space confinement" and either angling the SUV or backing the vehicle into an adjusted position that will allow you the chance to gain "The Mechanical Advantage"?
 
Last edited:

coolasice

Member
Oct 27, 2013
1,019
Northern Maine
If I turn my steering wheel all the way to one side I can get my air impact in there with my 18mm deep socket and zip them out easily.

In the rear, a good quality wrench and a big hammer to loose and tighten the bolts.
 

Jkb242

Original poster
Member
May 19, 2019
239
CLT
Indeed you are correct, if only I was working on the front brakes. I’m looking forward to the improved access that might be better on the front but the rear one are Terrrible!!
 

budwich

Member
Jun 16, 2013
2,027
kanata
your best bet is heating the thing up with any kind of torch. Let it sit for a bit there after. Further, heat the thing up well while you have your socket or wrench sitting in the freezer. Once heated, get the frozen socket / wrench and attempt to loosen. The increased thermal shock will likely help significantly. I have used this a few times on stubborn o2 sensors and differential fill plug... works well when nothing else would do.
 
  • Like
Reactions: Mooseman

Forum Statistics

Threads
23,273
Posts
637,499
Members
18,472
Latest member
MissCrutcher

Members Online