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Breaking rusted damaged frozen bolts free - advice


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I'm looking for advice on best method to remove rusted bolts with damaged heads on the front caliper brackets. The bolt heads have lost there 6 sided shape due to 20 yrs of rust damage. Tight space to access bolt is also an issue. Thinking about drilling out most of bolt and using one of those extraction tools (best tool/brand to use) after lots of PB blaster. Thoughts?

 

My goal is to get caliper bracket off so I can replace front rotors - if I damage brackets in the process that's okay - I'll replace brackets and mounting bolts.

 

Thanks,

 

Milty

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First, be sure the bolt that looks rounded off is actually a hex bolt. There is a guide pin that looks like it should be a bolt, but it has no head. Not sure what year/model you have, but on my '93 Legacy, the pin I'm referring to is part number 8 on the exploded view. Removing the single bolt allows the caliper bracket to pivot on the guide pin and out of the way.post-50719-0-08954300-1477331239_thumb.png

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Cut the bolts and/or bracket off.  Dremel, sawzall, angle grinder.  The time investment screwing with the bolt isn't worth it. 

 

The bracket isn't threaded so you just need to cut the bolt head off to get it to come off. 

 

If you drill it - drill it such that the rotation of the drill bit is in the "unthreading" direction of the bolt. So if it's from the bolt head side you use a left-handed drill bit.  If it's from the bottom of the bolt and you're "pushing" the bolt out you drill using a right handed drill bit.  If the drill bit is a little smaller than the bolt diameter, the drilling motion and subsequent heat of the drilling can turn the bolt/remanants out.


Drill it out and helicoil it

Or just cut it all off and start over - brackets are easy enough to find.  I've got a few dual piston caliper brackets lying around - though there are a few varieties.  Plenty of people ahve good ones lying around or buy them from a yard out west/south with no rust:
www.car-part.com

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Heat, kroil or PB Blaster or wax when hot or 50% atf/acetone and one of those bolt-grip sockets from irwin.

 

The wax trick is very old school and has a good reputation, have never tried it myself. Trick is to get the correct part a little hotter than the other.

 

If you can get the rotor off (breaking it?) you can apply whatever stuff to both sides of the bolt.

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Wire brush and chisel off any loose scale on the head of the bolt. PB or other penetrating oil on it. Then hammer on a slightly smaller socket.

I've used a dremel before to cut new flats on a bolt head so I could use a smaller socket on it. Probably tricky to get a dremel into that space behind the bracket though.

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Had a similar issue with my 97 OBW when replacing pads a few months ago- one of the bolts was really rounded. I was luckly able to get it off with a vice grips. I got replacement bolts from the local Subaru dealer and changed them all on both sides just to be safe. I tired to find replacement bolts at Advance, Auto Zone, Home Depot, etc but none had the right size or right quality. In the end Subaru dealer had them for $2.something per bolt.

 

You might also try to use a ratchet wrench which save you a ton of room. They usually come as 12-point which aren't great for rounded bolt heads but if you look around you might be able to find a 6-point ratchet wrench. I got these for doing brake jobs and they are just perfect and totally worth the few bucks of cost.

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Thanks for the advice - I tried a ratchet wrench 6 point initially - bolts so misshapen due to rust - had no luck. I have a local auto parts store - Levine auto parts that carries tons of hardened (tensile 8 I think) metric bolts - I need to stop by and see if they have bolts I need otherwise I will order from Subaru.

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If there is anything left of the rounded off bolt, I have taken an old 3/8" drive socket that is just slightly smaller then the bolt head.  It will be a socket that I don't care about, and I will then hammer down the socket over the bolt head. Often, this will remove the bolt or nut. However, what remains in the socket may be difficult to remove, so have thrown away the socket with rusted bolt or nut inside.

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  • 5 weeks later...

Finally found the time to work on my son's Sub. I purchase extractor socket set and an angle grinder - awesome tools - both front upper bolts on caliper bracket were removed using extractor socket and angle grinder on remaining two  bottom bolts.

 

Now - the step I don't love: bleeding all four brakes - first off - 20 yer old car - more rust on this bad boy than steel - bought 4 new bleeder - soaking current ones with PB Blaster - praying to the good lord I don't snap off bleeders and spend either hours trying to extract and save calipers or ending up purchasing calipers - I've gone through this process a dozen times before - I would appreciate hearing your DIY advice on breaking free bleeders and or any tips beyond telling my son pump the brake - hold it - on and on. Please advise.

 

Thanks....Milty

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Soak it.

 

Get it to move first with a 6 Pt socket. Do not use a wrench first. Unless there's a flare wrench or monkey wrench with superb grip.

 

Torch?

 

I'm sure one could bleed the brakes with the banjo bolt instead of the bleeder screw. But it may require setting up the caliper in a way the banjo bolt is higher and would be messy.

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I've used torches on the caliper area around the bleeders, make sure to bleed out all the cooked brake fluid.

 

Running a drill bit the same size as the bleeder hole all the way down, lightly, will ensure all the crud is out giving the penetrant you spray down the hole it's best shot at working.

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