Rear Spring Perch

[oldmanandakid]

What is the correct ID for the rear spring perch? The new bushings I have measure .75 in. OD. which is considerably larger than the .69 in OD front bushings. I looked everywhere but the right place and cannot find the correct ID perch measurements.

The reason I ask is that will have to drill out the existing bushing after exhausting all of the tricks I can find in the old threads for bushing removal including; heat-2 times, pushing with an old bushing on all-thread, driving with a bushing driver and pulling by threading the inside of the old bushing and pulling against the perch plus cutting 2, 3 then four relief cuts with a hacksaw.

The drill seems the only alternative left but the existing ID seems more suited to .69 in rather than .75

[BobbyG]

They are little buggers I can tell you that !I tried to get mine out without success - but I have the rear end out for some work and with easy access I managed to get them moving.

I cleaned up the area with a wire brush in a drill - so that I could see the edge of the steel bush in the housing - then I heated it up with a propane hobby torch - and then went at it with an air chisel - and the 1st one slid straight out.

The 2nd one was a bit tougher - I tried to cut the bush with a jigsaw - I got a little way in before I gave up and resorted to more heating and air chiselling - after a while this one slid out also.

I think it is the initial getting them moving once they are on their way it is easy.

I had tried a chisel and a hammer - don't bother with that method - the air chisel set on lightest setting with a suitable size bit is ideal as it kind of 'shocks' it out of there.

I will measure that ID for you in a bit and report back.

Bob

[BobbyG]

[BobbyG]

The bush in mine had worn more at the bottom than the top and I was not wanting to drill or ream it out as I could not be sure of just taking the bush out and not the hanger itself also it must be straight/square as it were !

I would try to push it out rather than drill it if possible.

let us know how you get on.

[oldmanandakid]

How much heat can the perch take. I've been a little hesitant about applying too much, not wanting to alter the temper of the metal.

We've started drilling out one side in hope that lightning will strike the other side before we have to take this drastic measure there too. Thanks BobbyG, we're drilling out to .75 in.

[BobbyG]

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You don't need to heat that much it is just a case of letting it expand and contract and as it does it breakes the rust bond between the two parts.

Do try an air chisel with a rounded end.

Good luck

Bob

[QGolden]

I asked the same question here regarding how much heat the perch could take. I had the same concern 'cause mine was so corroded that I could not find the bushing through the rust! But I made a drift pin that was turned down to fit just inside the bushing and turned a shoulder that was the same diameter as the bushing. I used a new bushing for the measurments. Then I used the smallest torch tip and heated the bushing in one narrow line, from end to end, right up to to cherry with slight surface bubbling. I have found in the past that it seems like I have better luck removing something from a cylinder if I only heat a small portion. If I expand one small area about 3/8 inch wide the full length and leave the other side cool so it does not expand, pins seem to loosen up better. After the heating, two hits with the drift and my biggest Ball Peen hammer and she moved.

[oldmanandakid]

After reading Brent's post on heat shrinking metal I decided to try that on the bushing I had planned on drilling. After three heat/cool cycles I hit the bushing with the saws-all, heard a reassuring ping and half of the bushing flew out. I easily punched the remainder out. It's on to number 2 today. QGolden I'll keep your technique in mind. Thanks for the input guys. The kid is calling this the most frustrating job yet. I am not so sure but it's close.

[QGolden]

Hey, one other trick I have used. If you can buy a can of electronics component cleaner. I think it is also sold as contact cleaner. You need the stuff that is a liquid in the can. If you turn the can upside down an ultra cold liquid will come out. It will frost a metal piece instantly. So heat the housing, and just as you are ready to strike the drift, have a helper spray the INSIDE of the bushing. The 100 or whatever below zero will shrink the bushing. That with the expanded (heated) perch should help.

I have heard of using this contact cleaner on stuck bolts where heat could not be used. Spray the bolt, let it frost up real good and it is supposed to shrink and break the rust. One mechanic at a paper mill told me he uses it on bolts, and as soon as he stops spraying, he hits it with Kroil. The as the bolt warms, the cold temperature wicks the penetrate into the threads. Again I have not tried it, but it sounds plausible.

[oldmanandakid]

The last bushing hammered out today with only moderate effort after the heat shrinking treatment. Golden I'll keep that freeze method in mind for the next stubborn project. Thanks to you and BoobyG.