The dreaded RTABs

[SwissCheeseHead]

I'm really surprised that there aren't any DIYs for the RTABs. From what I gathered, brake components, shocks/springs, and half shafts have to come off before being able to take the trailing arms off. Then it's nuke the bushings from outer space, then a getting a shop to press in the new bushings, placing a pipe in the middle so that the trailing arm doesn't bend. Is there anything else I need to know? I'm pretty sure my bushings are done, as I hear clunks and creaks over big bumps in the road. Also going to change out my Vogtland springs and do the seals on my diff while i'm in there. Any thoughts or advice would be helpful. Was planning on burning out the rubber on the bushing, then hammer and chisel the metal sleeve from the trailing arm to remove.

Im kind of dreading this, and I know my car will be out of commission for some time. Yuck.

[south42]

Have you looked at you dog bones yet? Could do the same thing.


Andy

[Neel]

A very good friend of mine, we've known each other for over 10 years, is my go to mechanic when I cant DIY stuff. He has numerous BMW's, e30 m3, an e23 745i turbo, and some other cool bmws in his family. He saw I was researching RTAB's (he knows I have an e34), he looked over shook his head and said its not worth ruining our long standing friendship.

I'm looking to tackle this soon LOL. Good luck, god speed.

For getting the new bushings in, ive heard marine grease is a good idea. I've also thought about placing the new bushings in the fridge for a couple of days to get them to shrink as much as possible to get them in.

[kouks]

Here are the Cliff Notes on this project, from the research I've done so far. I'm about to do this myself.

1. Raise rear end
2. Remove wheels and brakes (you will need to disconnect the brake line and bleed brakes later, for ASC+T cars, do not loose too much fluid otherwise you need dealer to do it)
3. Remove drive hubs
4. Remove dog bone
5. Remove Lower shock mounting bolt
6. Disconnect trailing arm bushings from frame
7. Get new bushings, it helps if you freeze them at least overnight.
8. Call local shops that have a hydraulic press and ask if they can press out the old and press in the new bushings (you cannot do this without a press efficiently)
9, Install in reverse.
10. Bleed brakes
11. Drive car

This is easier said than done, but the big deal is you need a hydraulic press. I have access to one but its a 45 minute drive away, I called a shop a few blocks away and they know about BMW trailing links, have a press and will do it for $67...deal.

Good Luck

[SwissCheeseHead]

Thanks for the responses. It's probably not the dog bones, as they were replaced a few years ago. Over the winter, there was a crunch in the rear, and as I was investigating, I sprayed some silicon lube on the RTABs, and the crunch was gone after that. Now that it's spring heading into summer, with a lot of rain this year, I suspect that the spray up has washed away whatever lube was in the bushing and now it's back with a vengeance. There's a local place called Weaver Auto Parts that advertises that they do Press Work, so I'll probably go with them since I don't know of any other places. So it seems that it'll be a multi-day/weeks project. It really is a shame there isn't a more comprehensive how-to. I'm sure it's probably due to all the cussing involved with the project. Ugh, i'm really dreading this...

[Neel]

not more than me, i just stopped driving the car LOL

[BleedsBlue]

It's not fun, but it's possible to do this sans press. That assumes you replace the RTABs with poly, though, and that you are ready to fight them on the way out with heat, steel, and any other tool available to humans

If I had to do this, I would get Greg's tool, and replace them with OEM M5 bearings, because they seem to be indestructible for 200k+ miles. I have poly on my Touring, and per usual they are audible no matter what you do.

[laine34]

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I just did this job. You can use a cheap harbor freight 12 ton press , and it only takes about 15 minutes to R&R both arms. Without the right tools though, it's not even worth attempting.

The standard shop press has to be modified, insofar that the load shelf needs to be discarded. The shelf sticks out too far to allow the arms to reach the press piston. I just used some steel plates we had sitting around to make a new shelf, and some wood clamps to clamp the plates to the press frame. You also need the right size arbor to press through the arm. I used an old Baum RTAB tool arbor that I had.

Lastly, BleedsBlue is right. If your gonna setup to do this job, then use E34 M5 RTABS. They are awesome slide bearings that allow the arms to be torqued with the car unloaded (up on a lift or jacks). And if you go that far, might as well throw in some Ireland camber plates.

The arbor for the stock bushings is internet available. The only M5 RTAB arbor I've seen is the one Greg made.

However, If you need to get this car rolling, then take the arms to a shop and let them wrestle with them. Just make sure you torque them to the subframe with the car loaded—otherwise the chassis will vibrate your teeth out. (I made that mistake about 10 years ago and it took me months to figure out what was wrong.)

[SwissCheeseHead]

It's a second car, so I don't need this done ASAP once it's up in the air. but man, I already bought the standard Febi bushings, so I'll probably put those in.

I would LOVE to get the HF press, but I don't know how much I'll use it after this job, AND, I don't have the floor space to store it, so that's probably not possible.

Thanks for the pointer on having the car loaded when torquing it to the subframe. I'll have to reconnect the half shafts and shock to do that (I'm assuming?)

[Tre0Tre34]

Thanks for the pointer on having the car loaded when torquing it to the subframe. I'll have to reconnect the half shafts and shock to do that (I'm assuming?)

Oh yes. The car will not have the ability to sit at the correct level without the shocks and springs... Guess the half shafts would not NEED to be installed, but they shouldnt be in the way of the bolts you will need to tighten either

[SwissCheeseHead]

Thanks for letting me know! Would putting the rear end on ramps give me sufficient clearance when tightening? I don't have any, but would get a pair.

*big sigh* I really don't want to do this...

[Neel]

I picked up a set of rhino ramps, and theyve been pretty good so far.

[biasvoltage]

I would LOVE to get the HF press, but I don't know how much I'll use it after this job, AND, I don't have the floor space to store it, so that's probably not possible.

Make room for one. Seriously, I thought the same thing when I bought one 5 years ago, to press apart a motor on a 60s DeWalt radial arm saw. I figured I'd use the press once or twice and probably sell it. Turns out, once you have a press, all sorts of jobs that you never would have tackled before become easy. Replacing wheel bearing races in my F250? No problem. Replacing oil seals on the M5's differential? No problem. All of these DIYs where people are using allthread and sockets and stuff from the plumbing aisle, while lying on their back under a car teetering on jackstands, become a 30 second job. It has become indispensable.

[moroza]

An H-frame press is generally useful. It's my single favorite shop tool.

A press is not required for this job; a puller/threaded rod kit can do it just as well. EDIT: Not so. A few can do it, but these bushings are Really. #$%@ IN THERE. Grade 8.8 hardware is not up to the task. Actually, the geometry of the trailing arms makes it awkward to set up in a press in the first place.

You need to remove the axleshafts but DO NOT remove the hubs. It's unnecessary and you will probably destroy the rear wheelbearings doing so.

Plain ol' dish soap is a pretty good rubber lube IME.

Be thankful you're only doing ~$25/each rubber RTABs instead of ~$70/ea slide bearings (like on 740, 750, M5, and my car).

[93FIM5]

An H-frame press is generally useful. It's my single favorite shop tool.

A press is not required for this job; a puller/threaded rod kit can do it just as well. Actually, the geometry of the trailing arms makes it awkward to set up in a press in the first place.

You need to remove the axleshafts but DO NOT remove the hubs. It's unnecessary and you will probably destroy the rear wheelbearings doing so.

Plain ol' dish soap is a pretty good rubber lube IME.

Be thankful you're only doing ~$25/each rubber RTABs instead of ~$70/ea slide bearings (like on 740, 750, M5, and my car).

When I first tried to remove these I tried a threaded rod setup and had no luck. In fact even my 10 ton press requires a love tap with a hammer to bust the RTAB loose then they just slide out. I've done 6 sets of bushings/bearings now and I can't see a threaded rod working. Any pics of your setup and guidance? Also don't see soap being helpful as it's a metal on metal connection for RTABs with no rubber except internally. Look forward to your reply!

-Greg


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[moroza]

Somehow I thought the rubber RTABs (not the slide bearings) were straight rubber, without a sleeve. Of course they're not; I was thinking of the rear swaybar links and subframe mounts.

[SwissCheeseHead]

Yeah, the bushings are encased in a metal sleeve, so it seems like it's going to have to be pressed in from what I've seen and read. I'm not going to waste my time with a DIY tool, as a few other threads have stated, that it takes way to much time anf effort to get them fitted with a tool.

I try to keep my garage clean, but having an H-frame press sitting there probably isn't going to be ideal...as much as I'd love one. Who knows, maybe I'll get one anyway...it's so cheap.

[BleedsBlue]

Somehow I thought the rubber RTABs (not the slide bearings) were straight rubber, without a sleeve. Of course they're not; I was thinking of the rear swaybar links and subframe mounts.

RTABs on a few other common BMW chassis are that way (E36, etc), and dish soap (plus freezing the bushing) are definitely the ticket in those cases.

The absolute terror caused by that metal on metal friction in the E34 is why I don't ever see replacing RTABs with "regular" E34 bushings; it's got to be poly or M5 bearings IMHO.

[Onizukachan]

Yeah, the bushings are encased in a metal sleeve, so it seems like it's going to have to be pressed in from what I've seen and read. I'm not going to waste my time with a DIY tool, as a few other threads have stated, that it takes way to much time anf effort to get them fitted with a tool.

I try to keep my garage clean, but having an H-frame press sitting there probably isn't going to be ideal...as much as I'd love one. Who knows, maybe I'll get one anyway...it's so cheap.

its actually 3 concentric metal sleeves apart from the outer one.
Very easy to burn out with map gas. You can do it with propane too, but you have to heat the sleeves, don't try to burn the rubber directly. Won't work.
I used a hack saw to cut nearly thru the outer one, tapped it with a chisel and bent it out.
Once i figured out the trick to it, getting the old rtab out took less than 10 min per bushing.
Getting the arms out was a kettle of fish, but doable.
Repalced with kmac poly adjustable rtabs, properly lubed, and never had a squeak.

[supa7]

Three years later, here's a 10-year flashback for the poor souls who don't have access to a press to remove these dreaded bushings: http://www.bimmerboard.com/forums/posts/503785

It has pictures to show the hacksaw and chisel method mentioned by Onizukachan.

Putting new ones in can be done by freezing the RTABs overnight before sliding them in with a little soap.

[jehu]

what are the manifestations in handling to indicate replacement is required?

[Tristan36]

did mine about 3 months ago was able to do them with out taking the trailing arms off but I used an Air hammer to push them out then slide some poly bushing in place of them. the air hammer works great just need to have the right attachment.

[xcastaway]

Dayum, given the godawful bang mine came out with, on Moroza's 20 ton (?) press that was twisting itself into knots in the process, I'm surprised that anything short of a good press would touch them. And he had to build a custom x brace in order to have a shot at doing it. The slide bearings went in easily in comparison. The removal and re-installation of the arms is a pita, but quite doable.

[5mall5nail5]

I did mine years ago - it was not pretty. SE PA car. Bushing sleeves were fused with RTA's. Greg M5 and I exchange back and forth - what we came up with was just south of insanity.

[theBMWbeast]

Is this tool still available for rent? Hoping to swap in some 750il trailing arms soon and want to do the bearings...