Posted on 03/20/2017 9:07:15 AM PDT by Paul R.
Advice needed: It's either corrosion or a gorilla with a wrench, or both, but I cannot get the brake caliper bolts on our Ford Explorer out. FoMoCo exacerbates the problem by using bolts with shallow heads, so it is difficult to keep a socket on them. I have tried various penetrating oils such as PB Blaster, smacking the bolt heads with a medium hammer, etc. to no effect. More info. in my 1st comment...
Another poster had the right idea when he simply said, "leverage". One tip, that I almost hesitate to share, is using two wrenches, end to end. Sometimes when you have space constraints it's your best option. You put the box end of the correct size on the bolt head. Then (and this is the tricky part) you take a second wrench and slip its box end over one jaw of the open end of the first wrench. It takes coordination. You need to put the second wrench over the jaw that is facing the direction that you are going to pull. The two wrenches will lock together as long as you maintain tension. It's very easy to hurt yourself doing this, so I'd strongly advise not hurting yourself. Otherwise, "knock yourself out".
Noted on the impact wrench — my plan is to try an air wrench. Hopefully my portable compressor (1.4 gal, 2.4 cfm @ 90 psi) can power it for at least short bursts.)
I have a small battery power impact wrench. It came as part of a combo cordless drill and impact wrench set, but its “impacts” are pretty weak — I only use it on small stuff I’m trying to cajole loose, such as a #8 screw at most. I remember another friend had a hefty battery power wrench with big honking ‘ol Ni-Cad batts. I’m pretty sure it would be too big, as you say.
My mechanic friend said they run into low profile bolt heads sometimes, but (being as they are a fully equipped 4-bay shop, much as you describe) they are only occasionally a problem. Why Ford would use such here is hard to say - as a tiny part of a weight reduction program is the only reason I can think of.
Heat the nut then apply candle wax to the top of it allowing it to melt into the threads. Should loosen up immediately.
I have never had to replace a Caliper on a vehicle I have owned under 150000 miles.
I find that many vehicles that are brought to fix are poorly or no maintenance until something is “grinding”. It is those vehicles that frequently need new Calipers.
Ok, I can go with that. (It’s a bit of a relief!)
In this case, the Explorer has under 75,000 miles on it & was garage kept all but last year. But I will check for any signs of corrosion or sticking of moving parts, of course.
The Toyota has over 148,000 miles on it, is 13 years old, has been kept outside all its life, and it appears the guys who put in the last pads did not do anything beyond putting in new pads, so a problem with a caliper there is less, uh, unsettling.
I really think this (Explorer) bolt problem is my lack of an air wrench, the oddly shallow bolt heads, and either some corrosion / no anti-seize in the threads or someone torqued in the bolts too enthusiastically, last time around.
Maybe it’s “all of the above”. (”All of the above” seems to happen a lot.)
Thanks again!
Ok, I was delayed again by rain, but, we were able to get the caliper bolts off, today.
I picked up an air wrench, but, it also failed to get the bolts loose. I was stunned. Possibly my compressor does not have enough air flow, but, I tried multiple short bursts, with the idea that surely the tank could supply enough air for two second long bursts. Air pressure @ the tank is plenty adequate, and the engaged surfaces of the bolt heads “shinied up” quickly / nicely from the impacts, but, no luck on turning the bolts.
The solution was to grind off the bevel on the 17mm socket, use a longer (25”) breaker bar, making sure the bar stayed @ 90 deg. to the swivel head (one HAS to turn the front wheel for enough clearance). Then I hung on, as tight as I could, to the swivel head and socket, to keep it “square” on the hex head while putting “some” torque on the bar, and my wife gave it all she had @ the handle of the breaker bar.
THAT did it.
The bolt threads look clean, with no sign of thread-lock or corrosion.
Obviously these bolts are in a spot where they CANNOT come loose in use. But, that said, I would estimate breaking free the tightest required ~180 ft-lb. of torque (95 lb. wife, ~22” out, pushing down, plus maybe 20-30 ft-lb. I could contribute from my position.) These bolts measure (at the smooth part of the shaft) 0.390” dia., very close to a 3/8” bolt. A table I checked says that a 3/8” Grade 8 bolt is good for 232 lb-ft. max. Dang...
The bolt is a 17mm washer head bolt, with the height of the head only 4.5mm (above the washer portion.) The shallow bolt head height really was the biggest part of the problem, as it made it tough for me to get enough torque applied.
BTW, I found some rather scary information pointing against the use of anti-seize on these bolt threads — will relocate and post...
Whups - I “lost” you two... :-)
Ok, I was delayed again by rain, but, we were able to get the caliper bolts off, today.
I picked up an air wrench, but, it also failed to get the bolts loose. I was stunned. Possibly my compressor does not have enough air flow, but, I tried multiple short bursts, with the idea that surely the tank could supply enough air for two second long bursts. Air pressure @ the tank is plenty adequate, and the engaged surfaces of the bolt heads “shinied up” quickly / nicely from the impacts, but, no luck on turning the bolts.
The solution was to grind off the bevel on the 17mm socket, use a longer (25”) breaker bar, making sure the bar stayed @ 90 deg. to the swivel head (one HAS to turn the front wheel for enough clearance). Then I hung on, as tight as I could, to the swivel head and socket, to keep it “square” on the hex head while putting “some” torque on the bar, and my wife gave it all she had @ the handle of the breaker bar.
THAT did it.
The bolt threads look clean, with no sign of thread-lock or corrosion.
Obviously these bolts are in a spot where they CANNOT come loose in use. But, that said, I would estimate breaking free the tightest required ~180 ft-lb. of torque (95 lb. wife, ~22” out, pushing down, plus maybe 20-30 ft-lb. I could contribute from my position.) These bolts measure (at the smooth part of the shaft) 0.390” dia., very close to a 3/8” bolt. A table I checked says that a 3/8” Grade 8 bolt is good for 232 lb-ft. max. Dang...
The bolt is a 17mm washer head bolt, with the height of the head only 4.5mm (above the washer portion.) The shallow bolt head height really was the biggest part of the problem, as it made it tough for me to get enough torque applied.
BTW, I found some rather scary information pointing against the use of anti-seize on these bolt threads — will relocate and post...
Something I stumbled on...
http://www.explorerforum.com/forums/index.php?threads/tighten-your-caliper-bracket-bolts.192818/
Also BTW, a web search for images of “Ford Caliper Bolt” turned up NONE with a head as shallow as the ones I have.
“... my wife gave it all she had @ the handle of the breaker bar.”
Well shoot! Why didn’t you ask your wife to get them off in the first place? After she brought you a beer to enjoy while you watched.
Just kidding! (and pinging Windflier)
Congrats, maybe they just way over-torqued them.
Are those two bolts on the caliper on the other side of the car also shallow headed?
Too funny!
Good job, Paul.
A Ford tech would have been expected to finish that in 1 hour.
1.4 if turning rotors.
You just lacked proper tooling, and or you have hot dog weiner arms.
Take your wife out for dinner for bailing you out.
Well, if “proper tools” includes a socket ground down to eliminate the bevel, I concur with that part of it!
There just wasn’t any way (even after grinding off that bevel) for me to keep the socket on the bolt head and apply enough leverage (almost enough to shear the bolt) from 2 ft. away, without it being a 2 person job.
Now, could Hulk Hogan do it in his prime? Well, yeah, probably...
Wifey’s reward was me setting up her tablet with a nice monitor hookup so she can play vids on the monitor screen for her kids’ class @ church. :-)
BTW, I also agree, a Ford Tech or other professional mechanic would have a GOOD air wrench w/ the car on a lift, to make short work of it. But, then again, I’ve learned some things, and we had a pretty fun thread!
Yes.
I’m almost tempted to replace them, but I understand they are some sort of “Super Grade 8” bolt.
OTOH, as long as either I or my 400-mile-away mechanic buddy always do the brake jobs, no way during my ownership will the bolts ever be torqued in at 180 lb-ft!
(I’m going to pick up a torque wrench too.)
I am a firm believer in torquing to spec. BTW, 180ft/lbs is about twice as tight as a normal passenger vehicle lug bolt tightness. But factory spec is always best and lets you sleep at night. Just don’t let your wife tighten them!
I believe “spec” for this bolt is either 80 or 85 lb-ft.
Thanks!
I’m still going to mix up some acetone + ATF fluid though, as with spring here, there’ll be plenty of “fix-it” jobs which may need it, coming up. I may try a couple other solvents, too. Xylene, for example, has almost as low a surface tension number as acetone (should “wick” nicely), and evaporates into air much more slowly. However, Xylene also migrates through the sides of a polypropylene bottle much more rapidly than acetone, so, unless in use, it must be kept in a glass or metal container.)
If I get a great result with something, I’ll “report” back. I’d better bookmark this thread...
Generally speaking, that sounds about right for a bolt with a 17mm head. I take it that you have determined that the sliders and piston/s are free? Oh, now I remember what it is that I keep forgetting to mention! Put something out of the ordinary on the drivers seat now. That will remind you to pump that brake pedal till it gets hard before you try to move the vehicle!
85 ft lbs is for the 2 caliper mounting bracket bolts specs.
The slider caliper bolt is probably about 25-30 Ft LBS.
Any tech just tightens with a six inch long combo wrench tight by hand and gves it a little palm bump pushing it probably a little over spec.. Goot and tight is what we call it.
It seems someone overtightened yours with an upper end impact gun.
There is a heck of a difference between a $39 dollar Taiwan impact gun and $500 Snap-On brand one.
Did you get new sliders and bolts?
Do you know what a stretched bolt looks like? Google it.
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