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-   -   will this work to install trailing arm bushings? (http://forums.pelicanparts.com/porsche-911-technical-forum/719340-will-work-install-trailing-arm-bushings.html)

rwilner 11-25-2012 04:45 PM

will this work to install trailing arm bushings?
 
I don't have a shop press, so put this rig together to "press" in the bushings. I'm wondering if others have used a similar approach to install trailing arm bushings.

http://forums.pelicanparts.com/uploa...1353894327.jpg

Chuck's instructions say to apply the press load on the inner sleeve, but I see no way to do this...shop press or otherwise.

I just mocked this up and it looks like it might be challenging to get them going in straight. If there's significant risk I'm fine handing this to a wrench to press in for me.

Have others done it this way?

Thx
Rich

78SCRSMAN 11-25-2012 07:58 PM

Mine are Monoballs but should be the same principal. First, remove the rubber inner sleeve from those. Next heat up the end of the control arm using a propane torch. After heating the metal outer bush should go in rather easily. May require some persuasion with a hammer and piece of wood.
The other way would be to use the setup you have there along with some heat but slide out those inner rubber bushes first.

JP911 11-25-2012 08:03 PM

As 78SCRSMAN explains, use heat. To make it even easier, throw the inner sleeves in the freezer for an hour. The heat + cold should have them slipping into place with minimal brutality required.

Driven97 11-26-2012 08:30 AM

Semi-related - is there any way to replace the bushings without removing the trailing arm completely from the car? I'd rather not pull the axle out if I don't have to.

rwilner 11-26-2012 08:42 AM

If you search, the consensus is that it can be done, but it's difficult. There is risk to damaging the inner bore of the TA bushing seat, which is soft AL, when pounding (or pressing) out the steel inner race of the bushing.

Having just completed the task of removing the TA bushing...I personally would not attempt it with the TA in the car unless I had seen it done before successfully or was doing it with someone that did. Even with the TA out of the car and positioned well in my bench vise, it was challenging to position the cold chisel to avoid nicking the ID of the bushing seat (although I did it successfully).

As a side note...for my old bushings, the part of the bushing exposed to the elements was quite dry rotted, but the actual bushing part was still quite serviceable. My advice is to really evaluate if the job needs to be done before diving in.

zippy_gg 11-26-2012 09:45 AM

Quote:

Originally Posted by rwilner (Post 7114212)
If you search, the consensus is that it can be done, but it's difficult. There is risk to damaging the inner bore of the TA bushing seat, which is soft AL, when pounding (or pressing) out the steel inner race of the bushing.

Having just completed the task of removing the TA bushing...I personally would not attempt it with the TA in the car unless I had seen it done before successfully or was doing it with someone that did. Even with the TA out of the car and positioned well in my bench vise, it was challenging to position the cold chisel to avoid nicking the ID of the bushing seat (although I did it successfully).

As a side note...for my old bushings, the part of the bushing exposed to the elements was quite dry rotted, but the actual bushing part was still quite serviceable. My advice is to really evaluate if the job needs to be done before diving in.

+1
I replaced my bushings (with the sealed monoball from ER) because I had everything out of the car (Engine + tranny, shocks, spring plates, etc...).
It is in fact quite easy to remove the TA if the spring plates are out; just a single bolt and not too much torque on it.

Driven97 11-26-2012 12:36 PM

Quote:

Originally Posted by rwilner (Post 7114212)

As a side note...for my old bushings, the part of the bushing exposed to the elements was quite dry rotted, but the actual bushing part was still quite serviceable. My advice is to really evaluate if the job needs to be done before diving in.

Thanks and sorry about the thread jack. I bought poly ones from our host since they were cheap and I am doing torsion bars / spring plate bushings anyways. Looks like I'll just pull the one bolt since I'll be in there and see if I can get the old ones out. Monkeying with the brake lines is not something I'm interested in at this point.

tobluforu 11-26-2012 01:24 PM

Heat the banana arm good,freeze the bearings and work fast or you will do what i did which was getting them stuck half way in. These were monoballs and I had to be bailed out by a shop.

Chuck Moreland 11-26-2012 08:58 PM

Hi Rich

You can use threaded rod or a bolt to draw the bushing in. We do this in our shop when we install the bushing with the arms still in the car.

However I suggest doing it one bushing at a time to minimize the propensity for the bushings to get cocked. It's also helpful if the bolt is M14, the snug fit in the thru-hole helps to keep things square.

The first bushing will seat easily. It is the second bushing that gets problematic. I will explain;

The bushing halves have a cylindrical steel core at the center. When both bushings are fully seated, the steel cores touch in the middle. This is so the cylindrical core carries the tension of the bolt that secures the bushing to the chassis.

The problem is the if you press on the steel core to drive the bushing into the arm, the rubber will deflect some. Thus before the bushing outer shell is fully seated, the cylindrical cores will touch in the middle. You will then not be able to push any further and the outer shell will remain off its seat by the amount of the rubber deflection.

Two solutions;

1) Don't apply the load to the cylindrical core, use a properly size bit of pipe to put the load on the flange of the outer shell. Thereby the rubber is not loaded and does not deflect. This works great, but you need a bit of pipe with a fairly precise ID size.

2) Go ahead and press the cylindrical core, but don't distribute the load around the already-seated bushing. Use a piece of pipe (or a really big socket) to distribute the load around the seated bushing and onto the arm itself. With this approach, the rubber still deflects but the rubber of the already-seated bushing similarly deflects, thus allowing the second bushing to fully seat. With this approach, you don't need such a precisely-sized pipe for load distribution.

rwilner 11-27-2012 06:28 AM

Chuck
This makes 100% sense. For method 2, It took me a second to understand what you meant by both rubber bushings deflecting when inserting the second bushing, but now I understand that the stout center piece of the second bushing will be pushing on the first, already-seated bushing, causing both rubber portions to deflect in the same direction...makes sense.

I'll stop at the hardware store for an M14 bolt, washers, and an appropriate socket or piece of pipe whose ID is ~= to the ID of the trailing arm bushing surface. Bearing are in the freezer, waiting for install!

Thanks buddy!
Rich

rwilner 11-27-2012 08:50 AM

Quote:

Originally Posted by Driven97 (Post 7114651)
Thanks and sorry about the thread jack. I bought poly ones from our host since they were cheap and I am doing torsion bars / spring plate bushings anyways. Looks like I'll just pull the one bolt since I'll be in there and see if I can get the old ones out. Monkeying with the brake lines is not something I'm interested in at this point.

Matt
I'd think twice before installing poly bushings in this location. Do some searches here.

The bottom line: the rubber and monoball versions allow freedom of movement in multiple axes; the poly bushings do not, and as a result, bind, squeak, and generally ride poorly. (This is based on what I read and not on personal experience.) Some folks may be happy with the poly ones, but many were not; I don't think you'll find a single negative review of the rubber or monoball versions.

If you're going through the trouble of changing them, I'd spend the extra few bucks and get parts that will perform the way you want.

EDIT: Assume by poly, you meant polyurethane.

BK911 11-27-2012 10:29 AM

I used a bench vise to press in the bushings.

Driven97 11-27-2012 11:22 AM

Quote:

Originally Posted by rwilner (Post 7116465)
Matt
I'd think twice before installing poly bushings in this location. Do some searches here.

You talked me out of it. I was trying to figure out how the toe & camber adjusters work and realized that there has some freedom / compliance needed at that joint.

Monoballs are not legal for what I am building the car for, I won't bother replacing with rubber unless there's significant play when I get stuff apart tonight.

Thank you, very helpful.


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