rear end swap 4.08 to 3.27

[n/a]

Folks,

Never one to finish one project when I can intermingle nuts and bolts from another, I'm starting to drop my original rear end and install a "low mileage" 3.27 rear from a 280 SE 4.5. I gives me a chance to swap from small to large motor skills as all that dash work makes me tense! Anyhow, any tips on how to go about the swap would be appreciated. I've got the factory and Haynes manuals on hand and ready to go. The rear end is complete out to, but not including the brake rotors.  I intend to store the original rear in case I ever sell the car, so I'm hoping you purists won't be too offended.

John

PS I've got on hand a new, split boot for the swing axle, rear shocks, and something called a "driveshaft support" and a "driveshaft support bearing". Other parts I should swap out while everything's pulled? Seems like the universal joint should go, too.

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[jeffc280sl]

I understand from others that you need to make a small change in the 4.5 axle.  The cooling tube has to be removed and the holes closed off.  

I hope you have a manual transmission. I think the auto would be sluggish on take off.

Where did you find the axle and about how much did it cost?


Jeff C.
1970 280SL 4-speed

[n/a]

I do have a manual gearbox. I have hated first gear in that thing the 20 plus years we've had the car, so I'm hoping this will be an improvement. I like to motor off relying more on the inline-six's torque than revving the you-know-what out of it.

Anyhow, I located the axle on the west coast. It cost just under $1000 shipped Fedex ground to the opposite coast. I got it from www.online-mercedes.com and dealt with Luis. I was very pleased with the transaction, but then I haven't tried it yet! It was crated up very nicely, I must say. Let him know I sent you, if you drop him a line at sales@online-mercedes.com.

John

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[jeffc280sl]

Thanks John,

I know what you mean about first gear.  It's too low and second is just a bit too high.  Rear end switch sounds like the way to go.  Are you going to do the swap yourself?  I would change out all of the bushings and lower spring pads while you your at it.  I've changed out the trailing arm bushings.  You need to make a small tool but its not hard to do.  Same goes for the main mount that's in the trunk.  Mine was pretty bad.

Have you considered progressive springs? I have them and they make a nice improvement in handling.

Jeff

Jeff C.
1970 280SL 4-speed

[n/a]

I am attempting to do the job myself. So far, it doesn't look too bad, but then all I've done is support the axles and disconnect the emergency brake lines!

Any suggestions for parts sources, particularly for the progressive springs? Should I go ahead and replace the pinion bearing seal? The one on the car now is leaking horribly and it may be the "new" unit isn't only because they shipped it dry. It does look pretty clean, though.

John

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[jeffc280sl]

John,

You can order the progressive springs from John Olson at www.slmarket.com

I have been buying parts from http://www.europeanautomotive.com/
Not sure what they have in the way of axle parts.

Do you have the BBB?  I have it on CDrom. If you would like some more documentation let me know.

Jeff

Jeff C.
1970 280SL 4-speed

[n/a]

I do have the BBB (paper version) and the Haynes manual. I'm now at the point of finding wrenches big enough to loosen the "sleeve nut" at the center bearing. I may go ahead and lower the thrust arms so I can remove the springs, just so I'll feel like I'm making progress. I'll replace those spring pads and hopefully the bushings.

Anyone know what size wrenches I need to loosen the sleeve nut?


John Livingston
Newport News, VA
1968 280SL 4 speed manual

[jeffc280sl]

Hi John,

After looking around some I found some additional items which will need to be changed when you put the 3.27 axle in place.  You need a new pickup gear for the speedo and a different emergency brake cable.

I found a 3.27 axle in New York.  Since you have yours already are there any questions you can think I should ask them about in order to determine the value.

Thanks

Jeff C.
1970 280SL 4-speed

[George Davis]

John,

I think the sleeve nuts are 42 mm and 46 mm.  I use cheap hydraulic fitting wrenches in sizes 1 11/16 and 1 13/16, with a cheater pipe.

George Davis
'69 280 SL Euro manual

[n/a]

Regarding the speedo pick up gear, I've already talked with Palo Alto speedometers (paspeedo.com) and they'll clean and recalibrate the unit for the new ratio for under $200 (assuming they don't find any huge problems with the currently-functioning unit). I don't know of many questions you can ask, as I'm  a novice at this. Generally, the more complete the axle is, the better. Some say to make sure it's one with the compensating spring instead of the hydropneumatic set up, but it seems people swap those over fairly routinely. My guy sent me pictures and the mileage of the donor car, all of which you have to weigh against the credibility of the source. He also sent me a shot of a tag or ID - I forget exactly which - that proved it was a 3.27. I didn't want to end up with a 3.69, which I didn't think would make enough of a difference to be worth all the trouble. My guy also has supposedly done this swap a number of times and offered to help (albeit long distance) if I run up against any problems. (He was very convincingly enthusiastic about the value of the swap, BTW, particularly with the manual g-box.) I just sort of went with my gut as far as the guy I was dealing with and the price - there just aren't that many out there to directly compare it to. A  well-known supplier of MB parts wanted just about double what I ended up paying. That was pretty persuasive! Time will only tell, though, if I made the right decision.

John

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[n/a]

George,

Where might I find the hydraulic fitting wrenches? I  did a quick google search and didn't come up with much. I did find a listing for  46 and 41mm drive shaft wrenches at http://www.samstagsales.com/mbref.htm but having to e-mail them to get prices scares me.

John

PS Here's a standard to metric wrench conversion table
http://www.csgnetwork.com/wrenchsizetable.html
They agree with your 1 13/16" for the larger, but show a 1 5/8" for the smaller. You think that would be too small?
BTW As much as I use them, I'll probably come back as a cheater pipe in my next life!

quote:Originally posted by George Davis

John,

I think the sleeve nuts are 42 mm and 46 mm.  I use cheap hydraulic fitting wrenches in sizes 1 11/16 and 1 13/16, with a cheater pipe.

George Davis
'69 280 SL Euro manual

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[rwmastel]

I don't know anything about exchanging rear axles, but I do believe Samstag Sales to be a good company.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[ja17]

Good used complete 3.27  rear ends, out of dead  W108 4.5 Mercedes sedans can easily be had for $200.00 to $500.00 here in the rusty north!

Joe Alexander
Blacklick, Ohio

[n/a]

Now you tell me! The guy I bought from on the west coast was surprised I had trouble locating one back east, but the usual on-line salvage yard searches came up dry, along with calls to Virginia yards. Maybe I should get a spare!

quote:Originally posted by ja17

Good used complete 3.27  rear ends, out of dead  W108 4.5 Mercedes sedans can easily be had for $200.00 to $500.00 here in the rusty north!

Joe Alexander
Blacklick, Ohio

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[A Dalton]

<<He also sent me a shot of a tag or ID - I forget exactly which - that proved it was a 3.27. >>

 The ratio is Stamped on the case , driver side , on a machined flat in front of the axle outer tube flange mount.
 If it had a Tag on it , it is more likely not a ratio tag, but a Posi Tag..check it out cuz they take a special posi fluid.
If I remember correctly , the posi is the one with the added cooling tube. These hit the chassis if not capped.
 I have some in the barn and will take a closer look to be sure.....

[jeffc280sl]

A Dalton,

You say that you think you have some axles in the barn.  If so are you willing to sell one.  Please describe what you have.

Thank you

Jeff C.
1970 280SL 4-speed

[n/a]

More on wrenches:
I heard back from samstagsales.com very promptly. They said that 41 and 46mm wrenches are the correct ones for the W113 drive shaft. Below are their catalog numbers and prices, which actually do seem pretty reasonable. They take only checks or money orders. No on-line CC sales. - belay that - I read further down the page and they do take PayPal now. Cool!

SW4004-41 open end wrench                      $20.33
SW4004-46 open end wrench                      $25.54

John

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[n/a]

I went ahead and orderd the wrenches from Samstag. It came to about $55 with shipping and insurance. Pleae don't anyone tell me they have a stack of these in their barn free for the asking!

Next I need help with a spring compressor that'll fit the compensating spring. The strut spring compressor I already have on hand won't fit in the rather narrow gap between the coils.
Any suggestions for a source for this? (All this is vaguely reminiscent of my first suspension tweaking 40 years ago. I actually rented a shop's lift to install an EMPI camber compensator on my first car, a '61 VW Beetle. What a groover I was.)

John

John Livingston
Newport News, VA
1968 280SL 4 speed manual

[graphic66]

When I removed my compensating spring my regular spring compressor fingers were to thick, so I just took my bench grinder and ground away the fingers until they fit. The advice I received said it would be a lot easier with the fuel tank removed, but I did it with the fuel tank in and if I do it again I'm taking that tank out. I kept the compressor on the spring until I reinstalled it and it went back in a little reluctantly but it went in. My target job was the rubber boot replacement with a split boot. You may consider if the axle is out putting the one piece boot on as it just may be a more secure seal, I'm not sure what splitting the axle entails and it might be to much trouble. Remember when filling or draining your differential to have the axles level with wieght on the tires or jacks as the axle tubes hold quite a bit of oil and if they are sagging down you can overfill or not completely drain the old oil.

[jeffc280sl]

I'll second Graphic66's comments.  I also did it without removing the gas tank.  I think a lot of this job would be easier without it installed.  I was only able to get one side of the spring compressor on the spring.  This means you need to use additioanl brackets to keep the spring from popping out and injuring someone.  My reinstall was complicated by the progressive compensating spring design.  The coil is tighter on one end and the compressor would not fit.  There wasn't much to compress at that end anyway.  Treat the compressed spring very very carefully.  Lot of energy trying to bust out.

Jeff C.
1970 280SL 4-speed

[ja17]

Hello,
All the W108  V-8 engine 3.23 differentials had the cooling tubes, with or without posi traction.
You can relieve most of the energy on the compensator spring. Remove the right rear shock absorber.  Remove the two 19mm bolts holding the right rear brake caliper (do not disconnect the hose).  Move the caliper out of the way. Allow the axles to hang. Do this by placing the jackstands at the points on chasis where the rear suspension  thrust arm mount. The axles will hang down. The compensator spring will be nearly all the way extended. Remove the 19mm inner most spring bracket bolt first. The bracket will now hinge out of the way releasing the spring. To be on the safe side, use a spring compressor which should fit now that the spring is so far extended.

Mercedes used a wide variety of ratios in this swing axle package. The 4.10, 4.08, 3.92, 3.90, 3.75, 3.69, 3.46, 3.23. The most difficult to find would be the standard 3.75 on the 230-SL. However the much more common 3.69 is close and has disc brakes! some of the early V-8 engine sedans had the 3.46 which could make a nice substitute for a highway cruiser. The 3.69 versions and 3.92 versions are probably the most common in the SL's and sedans. There are also a lot of 280-SE 4.5 sedan donor cars with the 3.23 which may be a little too long legged for some W113 owners.

The lower ratios do create a little more strain on the drivetrain. It is like a person climbing a stairway taking three steps at a time instead of one!


Joe Alexander
Blacklick, Ohio

[jeffc280sl]

Joe,

Thanks for your insight.  You just made the compensating spring job a lot safer for me.  Thanks again!

Jeff

Jeff C.
1970 280SL 4-speed

[A Dalton]

As Joe said, the earlier 111, 3.5 had the 3,46 and 3,69. I believe the Sedan was 3,46  and the Coupe was  either/option.
 The 108 , 4.5s were 3,27 . I think the 3:23 is just a typo ??

[ja17]

Hello,
Actually the 3.23 figure comes directly out of the Factory "Technical Data" booklet (1972). In any case the difference between 3.23 ratio and 3.27 in insignificant.


Joe Alexander
Blacklick, Ohio

[n/a]

Thanks for the tip on removing the compensating spring. I'm about to remove that right shock absorber as we speak.

Regarding the ration on W108 4.5's. My materials indicated that it was a 3.23 ratio, too. However, others disagreed. Attached is a picture of the numbers stamped on mine. Sure seems to be 3.27.

I'm figuring on roughly a 20 percent drop in rpm in top gear going from 4.08 to 3.27. I can't swear, but it seems to me I was running nearly 3600 at 65 (I think the factory puts the figure at just under 18 mph per 1k rpm, which is about right) and the new ratio should drop that to just under 2900. Sounds good to me, but only time will tell.

I can always drop down to third if I feel the need to reminisce!

John

Download Attachment: 3.27.jpg
53.49 KB

John Livingston
Newport News, VA
1968 280SL 4 speed manual