R/R steering box removal - scale of 1-10 - Page 2 - PeachParts Mercedes-Benz Forum

VEGASTECH777 · #16 03-12-2008, 10:09 AM

My method for doing a steering gear box reseal is this. If all you are concerned with is an external reseal so it dosnt leak fluid you can take some small shortcuts and save a lot of time. First I drive the car and if the power steering is working well ( good hydrolic response) and all Im concerned with is to get it to stop leaking then its pretty easy.
Granted you will have to remove the gear box to seal it but you wont have to totally disassemble the box to the last peice.
I always remove the steering wheel horn button assy and verify that the wheel is installed properly. The line stamped on the steering shaft should be at the top (12 o clock) This insures that the turn signal cancel will work properly. And to see this line you have to remove the steering wheel nut or tappered allen screw. Next lift the vehicle on a lift if you have access to one. Remove the steering return hose, loosen the hi press hose nut all the way, remove pitman arm (notice the line on the arm and on the pitman shaft that line up.) You will line those up again upon reassembly. With the key turned to position one you should be able to turn the steering shaft to a position where you can get to the allen bolt on the coupling. Remove it. Its a 6mm allen socket. Sometimes with a univerasal on a long 3/8" extension. If you can get it with just the allen and the extension even better. Hit the extension a couple of times to ease the removal of the allen bolt. If you strip it your in a world of hurt. So I always use WD40 and put the allen socket and extension in the allen bolt and nail it hard once or twice before removal. Once removed I like to put a small chissel in the coupling slot and hit it to spread open the coupling a little. I usually leave the chissel in there for now. Have a helper hold the steering gear box and remove the 3 large chassis to box bolts. When you pull out the 3rd bolt tell you helper to get ready for the weight of the box and not to be a pussy about it either. You dont want that heavy gear box falling on your foot! It weighs probably 25-30lbs! If the box dosnt come out right away you need to use a pry bar to get the gear box out and away from the steering coupling. Once again be sure to hold that box! Now you should have the steering gear box out of the car.
Cover the fluid holes and do a good external cleaning of the box to get all the dirt and grit off. Blow it dry and you can now move to your work bench to start the reseal.
Work one section at a time. Remove the 4 bolts at the bottom of the box and completely remove the seal holder. Replace the large oring inside and the external seal using snap ring pliers and a flat screw driver and a seal pick. Lube it with vasoline and put it back on. Now move to the top where the steering shaft couples to the box. Remove the snap ring and carfully with a small flat screw driver pop out the small seal and replace it. In cases where it dosnt want to come out drill a real small hole only in the seal itself and screw a smal phillips screw in it and use a pair of pliers to pull it out. Well you get the idea now lube and install the new seal with the new snap ring supplied in the seal kit. Now you see the 4 bolts on the top plate? Remove those and slowly turn the steering shaft a little and this will help the plate rise up just enough to remove the large o ring and repalce it also using some vasoline replace the tiny oring that is just under that top plate and make sure it lines up where it belongs. Now screw back the other way and reinstall the 4 bolts. On the sides of the gear box you will see one circlip and a plug about 3/4' diameter. remove the circlip and with 2 flat screw drivers pry out the plug. There you will see a oring in the grove, replace it and put the plug back in with te new clip. Lets ee what am I forgetting? Oh yes there is a bolt on the bottom of the gear box that has a seal washer and when you pull it out and have the steering gear exactly in the centered position you will see an indentaion on the piston inside the box. This is there so you can put a pointed holding tool in there to center the box while you reinstall it to the car. You can simply sharpen an 8mm thread bolt at the tip to a pointed end and use it as your centering tool. This locks the box in the centered position for easier install. later remove that bolt and reinstall the plug that you took out with a new seal washer. Im falling asleep at my PC as I write this...I hope this helps you guys. I know its not the greatest explanation and Im sure I may have miseed something. But you can get the general idea. I had a long night and a good one at that!!!!

The date stayed over and fun was in excess. Amazing what a tiny chip of a Cealis can do! haha Oh well Ill check back later once Ive gotten some sleep. Take care....

meltedpanda · #17 03-12-2008, 10:26 AM

thanks vegas, since you have done several , where and what seal is usually the culprit for the persistant leaks?
I am still hoping to do the bottom seal while on the car and be done with it!

abe g · #18 03-12-2008, 11:40 AM

Plumbing supply has sheet material that is used a s flame retardant while soldering copper pipe. Abe G

donbryce · #19 03-12-2008, 03:35 PM

Quote:

Originally Posted by abe g

Plumbing supply has sheet material that is used a s flame retardant while soldering copper pipe. Abe G

Thanks Abe. I got lucky today, see my edit to the previous post. The guy also sold me some silicone RTV that they use to seal around flues, good to 500 degrees. Makes a great temporary (or premanent) tailpipe/muffler repair too. I told him I wanted to insulate and patch though, so I went with the asbestos packing....

donbryce · #20 03-12-2008, 04:25 PM

Thanks for the great contribution Vegastech777. I have the damn thing out now, so I'll put down a few observations. It really wasn't that hard to get the box itself out, just the stuff in the way.

- The exhaust pipe bolt nuts are somehow held into the manifold recess and are quite loose when the bolt heads are ground off. Both the bolt studs turned out easily once the tension was gone from the pipe flange collar. I could leave the nuts (square, not octagonal BTW) in there, and will clean up the threads with a tap later. Whew, thank God I don't have to take off that manifold to fix a mess! See pic01

- The upper bolt for the coupler doesn't have to be removed at all. As R. Wooldridge noted, it is easily seen once the cover at the base of the steering column is removed. I tried to turn it out, using a small bit and 1/4" wrench, (see pic 03) but realized that access with a suitable socket/rachet isn't possible until the column is pulled up, about an inch. Since this is the MB procedure to remove the coupler from the box spline (turn shaft until lower 6mm allen bolt is accessible, remove bolt completely, then remove steering wheel, pull turn signal unit out, remove 3 allen bolts at column top, move shaft up)(about 1"), there is no need to remove this upper bolt unless you are replacing the coupler.

- I turned the shaft so the open split in the coupling was facing down, then used a metal marking pen to accurately mark it's position vis-a-vis the spline on the gearbox. Very important to getting this back into the right location. Once off the car, I made punch marks to ensure I wouldn't loose this spot. See pic2. No problem with the pitman arm, as there are already marks on it and the spline shaft.

Quote:

Originally Posted by VEGASTECH777

Once removed I like to put a small chissel in the coupling slot and hit it to spread open the coupling a little. I usually leave the chissel in there for now. Have a helper hold the steering gear box and remove the 3 large chassis to box bolts. When you pull out the 3rd bolt tell you helper to get ready for the weight of the box and not to be a pussy about it either. You dont want that heavy gear box falling on your foot! It weighs probably 25-30lbs! If the box dosnt come out right away you need to use a pry bar to get the gear box out and away from the steering coupling. Once again be sure to hold that box! Now you should have the steering gear box out of the car.

- Wish I'd read that chisel idea before I tried to get the shaft/coupler off the spline. I did try prying, but noticed that the big nut on the box was starting to get bent up. I used a long, stout steel bar and a hammer, hitting on the shoulders of the lower bolt area of the coupling instead. The shaft needs to go up about an inch to clear the box splines.

- I removed the 2 bottom bolts from the box, loosened up the topmost one, then, on my back, I could hold the box up with my right hand while using my left to manually undo the last bolt. Yup, it's heavy alright, so if you don't think you can handle the weight in one hand, even for a few seconds, wire the thing up first so it won't drop suddenly.

Not steering box related, but the last picture shows the pitiful condition of my rear subframe mounts. There's no rubber left at all in the mount pockets! The weight of the subframe/engine, with the frame on jackstands, has pushed the bolt heads/washers about 1/2" away from the subframe.

meltedpanda · #21 03-16-2008, 01:43 PM

So one more time, and with what has been said. I looked closely at mine yesterday, the leak is the seal on the bottom. It LOOKS like I could remove pitman arm with puller and remove the three bolts to get at the offending washers, repair aand replace without removal from the car.
Reasonable or asking for trouble?????

donbryce · #22 03-16-2008, 05:52 PM

I'm just about to sit down and finish my thread on doing the re-seal, ala. Dave Petryk's excellent article. From what I've learned, and posted already, removing the box from the car is NOT A BIG JOB at all.
The worse part is getting the pitman arm off, which you'll need to do regardless. And that wasn't so bad at all, once I got the right puller.
The seal kit is under $20.00. The total time it took me to install all the O-rings and the 2 main shaft seals was about 4 hours. I did spend at least that much time reading the manual and Dave's article, and the thoughts of others here. I like to have done these jobs completely in my head before I even turn a wrench, but that's me.
Forget trying to do anything with the box on the car. Vegastech777's comment "Granted you will have to remove the gear box to seal it but you wont have to totally disassemble the box to the last peice." applies. But after you've got it out, just follow Petryk's procedure, which covers everything you'll need to know.
Tune in to my thread, I'm going to post up the results of doing the seal job....

VEGASTECH777 · #23 03-17-2008, 06:45 AM

Ive resealed the pitman arm seal with the box on the car on several 126s and the box on the 107s are the same unit. If there isnt anything in your way remove the pitman arm and unbolt the square plate thats at the bottom of the box where the pitman arm comes out. Pry it out and replace the large oring on the inside (it seals to the ptman shaft and does most of the sealing work and replace the outter seal that is held in with the circlip. Installing that outer seal is easy as all you have to do is push it in place by hand and put the clip back in. Now lube it up all nice with vasaline and reinstall it back onto the box. Take note of the position it was in when it came out so it goes back in the same way. Its been a while but Im almost sure it has a small oring between the plate and housing body like the top plate but maybe Im wrong cause its been at least a year since the last one I did. In fact it should be an inner oring and an outter oring and the seal where the clip goes. When you do it you will see its not rocket science and isnt all that hard. The hardest part is getting off the pitman arm.
Well what more can I add to help? Are you guys familiar with adjusting the play in the steering gear? OK at the top of the box is the adjustment screw with a 19mm lock nut. If you see a lot of theads showing (like 7 or 8) its been already adjusted a couple times and the gears are worn inside the box. If you only see 3-5 threads showing then the gears have room for more adjustment and the box isnt all worn out.
Start by using a deep 19 mm socket to break loose the nut. Just crack it loose and then hold the nut with a shorty box end wrench. Now using a 6mm allen on a long 3/8 drive extension turn the screw counterclockwise untill it gets tight. Now turn it back in at least 1/2 turn and holding the allen in position tighten the locking nut. Test drive the car and after making a turn if the steering dosnt return to the straight position on its own then its too tight. Go back and screw the adjustment screw in an additional 1/2 turn and test drive again untill its free enough for your steering to return as normal. Otherwise you will make a turn and when you let go of the wheel the car wants to continue turning! For you to better understand this adjustment the adjustment screw is attached to the top of the pitman shaft/gear and as you turn the adjustment screw counterclockwise you are pulling that shaft upwards and making it mesh tighter with the steeering shaft gear because the gear has a tappered cut. I hope I havnt lost you so far and you understand what Im trying to explain. Now another thing exists as these steering gear boxes get old the gears wear and you cant always get rid of all the play by adjusting it. For example your best adjustment without making it too tight still has 1-2 inches free paly at the steering wheel and thats as good as it gets for that particular gear box. So what do the sneeky gear box rebuilders do in order to give you the ILLUSION that there is no play? Ill tell you what they do. When they rebuild the box they add a little extra pre-load to the bearing at the top of the box where the steering shaft is. This gives it a slight tight feeling faking you into thinking the box isnt worn out but the 1-2" inches of free play at the steering wheel is still there. Ive done it before for those customers who say they are soon selling the car and dont want to spend the extra money. You know the cheap asses that still own the car a year later....hahaha

Now that preload adjustment can be tricky and is best left alone or only for seasoned mechanics that are real familiar with it. So all in all if you see the adjustment screw showing lots of threads dont waste your time. Just get another gear box to replace it with. And look for one that isnt showing much threads above the lock nut. I hope this was more help than confusion. Good luck guys and sometimes you will surprise yourself with what you can do on your own once you get into it. But if you get in trouble or over your head its always good to know a good technician that can bail you out. Good luck and good motoring my Mercedes brothers!

ctaylor738 · #24 03-17-2008, 07:58 AM

This is really good stuff. Thanks for taking the time to post it.

donbryce · #25 03-17-2008, 10:02 AM

I second that comment. I had 5 threads showing when I started, and I re-set to show the same 5 threads. I'm bound and determined to come up with a way to easily access and adjust the play with the box back on the car though, maybe look at cutting an access hatch/door through the firewall. I couldn't even see that screw/locknut from above or below, let alone get an allen bit in there and 19mm wrench on the nut. The manual shows a ridiculous 90 degree bent closed end wrench, kind of hooked to the nut from below.....maybe time to invest in some crowsfoot wrenches.
I read your comments on adjusting the steering worm play with great interest, and thanks for the heads up on rebuilds. (Reminds me of a shady transmission shop I know of, the owner carried small shavings of metal in his pocket to sprinkle in the pan to show the gullible customer he needed a rebuild). I set mine as best I could, but no way to really know if it's right without the right Ncm measuring tool. The box is still on the bench - any tricks to verifying that the preload is within reason?

meltedpanda · #26 03-17-2008, 07:36 PM

thanks bunches Vegas, looks like a plan!

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