replacing rear trailing arm bushings

[limble]

I'm 1/4 of the way through replacing the trailing arm bushings in my 79 911. The poly-graphite parts I ordered don't look like the original parts.
The original bearings are made up of two parts. A daddy thing on the left goes into the mommy thing in the middle. Metal and rubber respectively.
However, the replacement bearing on the right is a combination of the two and is all poly-graphite.
Is this new bearing correct?
Also while the two are copulating the shoulder height is greater than the replacement bearing.
What size washers do I need?

[TRE Cup]

we like to use either the elephant inner rear monoball or the oem bushings.
I am not a fan of the poly graphite because we have seen a) it takes some time to get them to fit right. Too tight out of the box b) tend to crack because of the loads imposed on them. We used to install them along with a silicone bronze sleeve we had machined up, but its no longer worth it since the elephant and other makes are available

[Zeke]

The direct answer to your question is, yes, that is the complete and full replacement. You will probably have to radius the smaller diameter edge to get them in all the way. Read up on old threads (search) and see how people have grooved and nocthed these to allow for some resident lube, usually a synthetic grease.

Or just do as Dave says and get something better. I used the neatrix kind and was satisfied with the performance given the amount of money spent. Hard urethane ones like you show are prone to the problems Dave mentions.

[dfink]

I am not sure about your year but on my 85' there is also an outer sleeve to the original bushing that has to come out of the trailing arm before the new bushing goes in. Kind of a pain to get out. I put in the monoballs to give better support. The point has to pivot all directions and the poly looks to be too stiff. I agree to either go original or monoball. If you do auto-x the monoball will put you into prepared class if that matters.

[Todd Simpson]

This was recently discussed here. Weltmeister banana arm bushings

You need play in that bushing to adjust toe and camber. Rigid mounting at that point is a problem.

And they ain't durable!

[limble]

The saga continues.
I ordered spring plate bushings and got these, shown in the top and middle figure. When you stack the two the overall height is too tall by about the height of the top bushing.
You need the radiused part to fit into the outer spring plate cover.
What I need is the shown in the bottom picture.
Question should I try to cut the bushing (middle part) or add a radius to it.
I measured the parts to get the dimensions so if someone else has different numbers please feel free to add.
Anyone else modified one of these?

[TRE Cup]

looks like you received the earlier 65-68 rear bushings. Return them and order these for the spring plates from our host:
Neatrix p/n pel-pp909976 for $64.05 set.
on the inner bushings for the control arms order 901 331 059 00 m100 at $48 x 4 for the set

monoballs are great if you get in there and lube , but i do not recommend them for a street car that sees a lot of miles- they WILL wear out if not attended to. The elephant polybronze is a great option for the spring plates, but again not needed for regular street use and they require periodic greasing (thru the nipples on them)

if this car is for sporting use AND you maintain it on a very regular basis, then the poly bronze outers and monoball inners is an option to consider

[dfink]

If you replace your rear bushings use the vise grip razor knife method. It is kind of like peeling it. Worked really well once I got the wifey to hold on so I could get a better grip with the vise grip. If you can't find more specifics on how to do this you just make a slice down the old bushing then force a screw driver down along the shaft (tube) this will produce a flap. Grab the flap with the vise grips and twist around the shaft (tube) while cutting next to the shaft (tube). By shaft I mean tube. Hopefully you find better directions but this method works really well. About 15 minutes per side.

[limble]

TRE Cup
I ordered:
PB-003 inner
PB-004 outer which is PB-003 with the extra radiused piece, see top figure in sketch.
They are for the 74-89 car.
Are the Neatrix inner and outer parts a different part number?

dfink, I added a little heat and the old part just peeled off.

[Walt Fricke]

Mike

What dfink is thinking of are the steel sleeves that are pretty firmly pressed into the big hole in the inner end of the aluminum banana arm (this is how and where you started this discussion, though it has progressed I guess to the spring plate bushings). Next comes the rubber, then the steel bushing with steel end cap, and finally the big through bolt.

I know that if you are going to use monoballs (which I favor, but I am a track guy even with my street SC) you need to remove the outermost steel sleeve, which two pieces pressed in from each side of the arm end. I had a heck of a time doing that - careful work with a small chisel until I had a lip a punch could work on, ending up with a crease internally through which I could drive a pointed punch and prise it out. Of course, once one is out you can get a purchase to drive the other one out. The second arm end called for much less blasphemy, as I had figured out a method.

Your pictures are not of these sleeves, as the rubber part fits inside them, not around them.

I don't know if you need to remove these sleeves to use those urethane replacements. Looks like you don't But I don't care. Just in case the previous posts haven't persuaded you, here is the deal: You should not use those urethane pieces, period. No, no, no. Throw them away. They are a bad idea. No one should ever have manufactured them, and no one should sell them.

The stock rubber piece (and the Neatrix replacement) can squish easily enough to allow the angle changes the suspension requires. The urethane pieces are too stiff for this.

Think about the geometry back here - how, for instance, is toe adjusted? By moving the axle forward or backward, right? That moves the banana, creating a different angle relative to the big bolt in the mount that goes through the center of the bushing. The same is true for camber adjustment. You need compliance there.

These adjustments on a stock setup are difficult enough as it is, having to deal with some resistance on the part of the rubber to taking up a new angle (small though it is). You don't want to make this more difficult. And then there are those posts where guys report actual wear and cracking, not just theory.

Urethane works just fine for the spring plate bushings, especially if you keep it lubricated. When I removed my front urethanes after fifteen or so years of use they were in fine shape - good enough to resell. The rears, where lubricating is tougher and which have a harder life, were worn some. But these bushings only deal with rotation in a single plane (and in the rear have the spring of the spring plate to deal with minor in and out changes). Not at all like the banana inners.

Sounds like you were persuaded to use Neatrix all around, though, in which case sorry for the diatribe against a bad part. I assume the Neatrix requires leaving the inner banana arm outer steel sleeves in place, for the same reasons the factory thought them needed (whatever those might be), so all is well. But I have never installed Neatrix stuff, as I learned to live with the harsher track pieces.

Walt Fricke

(ask me what I really think)

[dfink]

What Walt said.......

[msk1986911]

At the risk of showing my ignorance of things mechanical, does the car have to be realighned after the bushes are replaced, ie trailing arms and front and rear torsion bars? The car is an unmodified (I think) '86 coupe.

Thanks.

Mike

[dfink]

Originally posted by msk1986911
At the risk of showing my ignorance of things mechanical, does the car have to be realighned after the bushes are replaced, ie trailing arms and front and rear torsion bars? The car is an unmodified (I think) '86 coupe.

Thanks.

Mike

Simple answer is yes

[dtw]

Originally posted by dfink
Simple answer is yes

Due to this fact, and the extreme difficulty in removing the OEM bushings in-situ, I am a big fan of removing the trailing arms altogether to do this job. With the trailing arm in a vice, it is a piece of cake to get the bushings out. The only real extra work required is a brake bleed (assuming you already fully or partially dropped the engine - mine was already out when I did this job).

[William930t]

Realignment & ride height fine tuning after suspension service, whether front or rear is standard procedure

[beamonk]

How does one lube the monoballs without taking them apart?

[Walt Fricke]

One doesn't lube monoballs. It is possible to purchase rod ends with a Zerk fitting, but you'd have to do your own design and drilling ant tapping to deal with a spherical bearing. Typically these bearings don't need lubrication. And as for taking them apart, fugedaboudit. They aren't designed for that. They typically have a teflon or similar liner, which dosen't need lubrication.

I think it is quite possible to disassemble the front suspension and reassemble it without losing alignment. And you can come pretty close to replicating the previous corner balance, too. If you don't move the camber adjusters in the fenders (and there is no reason to loosen those three nuts), and you don't unscrew any of the tie rod adjustment parts (because you just pulled the tie rod ends out from the steering arm), you will be back where you were.

But in the rear all you can do is put things back together fairly close to where they were before. Careful marking of the spring plate's position vis a vis the banana arm will get you close. But most likely only close. Close enough to drive the car to the place of alignment.

Corner balance is trickier, though. And you will only be close, most likely. All of which means you will want at least to check the alignment of the whole car. And realign where it is off of whatever spec you want. And redo the corner balancing.

Walt Fricke