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Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 10:05 am
by Certified Lotus
Thanks for all the replies. The holes in the outer tube are near the bottom. Someone used set screws that were too long in a mounting collar for the adjustable spring perches and tapped thru the outer tube. So any oil in the tube will eventually drain out.

These tubes are bone dry. Probably the reason the shocks failed (no idea how long they were in the car).

Still need to know: what is the best way to remove the outer tube from aluminum bearing assembly and replace with a new one? Do I take a torch to the bearing assembly to heat it up and hope the tube will come out?

Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 11:55 am
by tvacc
Rather than replacing the tube, why not slip over the spot some sort of clamp to seal the holes. There is no pressure involved so it should not take much to seal.

Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 12:11 pm
by Certified Lotus
Good idea Tony. But I'm one of those guys who always wants to fix it right while I have things apart. So I'm on a mission to replace the strut tubes.

An example (fix it right) of that: I bought the entire bearing and seal kit for the rear diff and hub shafts. I wasn't having any problems, but I will have the housings out to change over to a new chassis and figured it would only be a few more hours of labor to replace everything. I'm adding measurable HP to the drive train. The weakest link always fails.

I'm pretty much a fanatic on everything I do. Do it once, do it right. And stay focused on the objective. :D

Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 1:13 pm
by tvacc
I agree that you should fix it right, but a very flat band, held in place with JB weld would hardly be noticeable and do the job without risking damage to the aluminum carrier.

Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 1:59 pm
by collins_dan
The way your adjustable platform was installed is not traditional. Typically a threaded band is welded to the tube. If you were to do this, then the hole would be covered and the adjustable base would be more securely installed. Dan

Re: Removing Rear Dampers

PostPosted: Thu May 21, 2015 9:00 pm
by billwill
I think the question of removing the outer tube has been discussed on here before, but I know not where.

Try a search for adjustable shock absorbers or for adjustable springs etc. because I vauguly recollect that it was in connection with fitting the screwed spring platforms.

Re: Removing Rear Dampers

PostPosted: Fri May 22, 2015 2:10 am
by nomad
Can't anybody weld anymore??? A few holes in the shock tube would be easy to fix unless the tube is completely rusted to the point that it would be hopeless.

Kurt

Re: Removing Rear Dampers

PostPosted: Fri May 22, 2015 9:04 am
by gjz30075
Certified Lotus wrote:Still need to know: what is the best way to remove the outer tube from aluminum bearing assembly and replace with a new one? Do I take a torch to the bearing assembly to heat it up and hope the tube will come out?


To answer the question: yes, heat the casting and the tube will slide out.

Re: Removing Rear Dampers

PostPosted: Fri May 22, 2015 12:54 pm
by Certified Lotus
Appreciate everyone's input and suggestions. I've decided to install new outer tubes from TTR. Since I am completely dismantling the chassis and have all the parts off anyway It's not really a big deal (at least I hope not).

From all the research I have done, the procedure is to warm up the bearing assembly (either in the oven or with a torch. I have both) and take off the tube. Installing new ones requires putting the tubes in a freezer overnight and reheating the bearing assembly slipping it on (or pressing it on with a press. I have that too).

Will let you know reality when I'm finished.

Re: Removing Rear Dampers

PostPosted: Fri May 22, 2015 1:21 pm
by elj221c
Certified Lotus wrote:I'm confused, the instructions that come with the TTR supplied Koni shocks say to pour some oil down the shock tubes to keep the shocks cool.


A long time ago I know, but when I put Konis on in '82 they advised to use antifreeze. (para 5)

Re: Removing Rear Dampers

PostPosted: Sat May 23, 2015 1:43 am
by nomad
Certified Lotus wrote:
From all the research I have done, the procedure is to warm up the bearing assembly (either in the oven or with a torch. I have both) and take off the tube. Installing new ones requires putting the tubes in a freezer overnight and reheating the bearing assembly slipping it on (or pressing it on with a press. I have that too).

Will let you know reality when I'm finished.


I've put a few bearings in aluminum motorcycle cases. If done right they just drop in.

Be prepared and work fast. If not using an oven you can trust to get to the right temp I always used the "spit" test for getting a good idea of the temp of the housing. As you are heating it spit on it and observe how fast the spit flashes into steam.

Of course...aluminum can be warmed too far and doesn't give you a warning!

Kurt
26/3754

Kurt.

Re: Removing Rear Dampers

PostPosted: Sat May 23, 2015 1:48 am
by Certified Lotus
Kurt, I have been wondering what temperature to set the oven to. Any suggestions in addition your spit test ?

Re: Removing Rear Dampers

PostPosted: Sat May 23, 2015 11:46 am
by cal44
If you decide to use a torch, use a large tip (#4 or #5) or rosebud. Go online or to the welding supply to see what temp sticks they have, they look like a pencil. Move your heat around the area (not getting to close to the metal with the tip of the heat) where the tube is inserted, never stopping in one place, never putting your heat on the metal tube. Heat, temp stick, heat, temp stick.......always moving......never stopping, moving methodically with slow to medium speed

Or, head over to a motorcycle shop or machine shop and ask the boys what is a good "general" temp is for relaxing the alloy to remove inserted items...........(ouch)

Here is your problem with general heating. You are also heating up the steel tube causing it to expand inside the alloy, so I'm stumped there. I don't know the difference in expansion rates of alloy vs. steel but dollars to donuts the alloy is faster.

Me likey the spit test...........shoulda' thought of that.

Re: Removing Rear Dampers

PostPosted: Sat May 23, 2015 2:59 pm
by Bud English
The one time I did this I was removing a perfectly good tube from a bad carrier so I can't advise on the removal. I carefully split the carrier with a hack saw. They were cheaper and easy to get then. Today I would have it welded.

Putting the new carrier onto the old tube went really smooth though. I heated the carrier in the oven to 325 degrees F (she was at work). If you use a torch, use a temp stick as suggested. Like Kurt said, aluminum gives you no warning. It just goes away. I put the tube in the freezer for a couple of hours. You could also use dry ice in the tube. That might give you a little longer work window although it's the aluminum that changes temp faster.

The key is to have everything marked showing the correct positioning of the relationship between the parts you want to end up with. You only have a short window to get it right or you're starting over. If the new tube is clean and smooth and everything is lined up square when you start you won't need the press. It slides together surprisingly easy. At least it surprised me. :)

Re: Removing Rear Dampers

PostPosted: Sat May 23, 2015 8:17 pm
by billwill
So there's nothing actually holding our rear suspensions together? Just heat assisted interference fit?