Time for a professional... - PeachParts Mercedes-Benz Forum

origamitect · #1 05-09-2006, 09:10 AM

The "simple" transmission swap has ballooned to epic proportions. If you all remember I have the frankenbenz with the transmission that went out. Found a tranny from an older 240D. Bemoaned the lack of a 46mm wrench for about 4 hours, realized the driveshaft could be compressed enough to disengage it from the rear of the tranny. Stripped out one of the starter bolts, had to weld a piece of 10mm allen on to remove it. Found another starter bolt from the guy I got the tranny from. Did a combination of sitting on top of the engine to guide husband with the mother of all extensions (reached from the rear of the tranny) to get the two top bolts off. Removed P.O.S. trashed tranny. Realized - hmm. there is no pilot bearing in there! That must have something to do with the trashed tranny...hmmm... time to feel really stupid for a minute. Tried to install new pilot bearing - and of course I have the 35 mm bearing trying to get in to the 34 mm hole. Bought two brake hones and honed for 10 hours to remove 1mm of material. Pressed pilot bearing in. (still didn't go in easy.) Installed transmission. None of the linkages match up to anything. Identify which linkage is which - mark to cut or lengthen as required, cut and weld to resize. Everything fits, but, reverse binds up coming out. Decide - well, I can live with going forward only for the short term, lets take it for a test drive. Hahaha. New clutch works, but! Somehow I have switched the linkages for 1st/2nd and 3rd/4th. So - I have to remember to shift in a backwards H.

Look at linkages and try to switch them back - now they all bind. ACK.

AND the friction plate seems to not grab at high RPM. ACK. What would cause this? I am at wits end. I really don't want to spend 600-1000 to have someone replace the clutch, but what are my options at this point?

Thanks in advance for your help.

t walgamuth · #2 05-09-2006, 07:22 PM

sorry you are having all the trouble.

this is one of those " i only had this one little part left over" stories, right?
sorry couldn't resist.

could you describe in a little more detail what the clutch is doing now?

tom w

origamitect · #3 05-10-2006, 02:56 PM

Clutch pedal is very stiff, seems very "high". At low speeds, (like coming out of first) have OK correspondence b/t engine revs and acceleration with clutch not pressed down. At the top end of first, the engine revs high without any additional transfer to the driveline. It gets worse at higher gears. If I get into second and punch it, no transfer of power. Just slips and the engine whines. If I back off the accelerator pedal, it will eventually grab. If I ease the pedal slowly, I can accellerate (slowly). Basically it seems like something is keeping the clutch from fully releasing. Something to consider, is I have a master cylinder for the later chassis series 240D. Had to get a slave for earlier chassis series 240D to fit on the "new" tranny. Wondering if the master/slave have to be matched (like if the bores are drastically different causing a hydraulic multiplying effect when there shouldn't be) Local mechanic thought perhaps the the slave piston arm is too far in keeping the release fork from going to "relaxed" position. Suggested I put some spacers between the bellhousing and the slave. As a test, I completely removed the slave and tried to start it in gear just to make sure the pressure plate was pushing. Seems to have complete grab - lurched forward and stalled with the brake on. Before the slave was removed, could start in gear without pressing the clutch pedal in - was just like starting in neutral. Going to try the spacers tomorrow night. Will deal with the linkages this weekend.

Stevo · #4 05-10-2006, 04:21 PM

The Haynes manual has a picture of the linkage which might help you.

The way your clutch is acting might suggest you have the wrong T/O bearing, which I know you dont want to hear at this point. On mine (both times) the clutch engaged at the very TOP or the pedal throw, which resulted in grinding going into gear. Yours does the apposite, which could mean I had the bearing you need and visa versa. Anyway, my guess is T/O bearing. Hang in there, you'll sort it out

t walgamuth · #5 05-10-2006, 09:27 PM

yeah, i was wondering about that. they come in different thicknesses. why? i dont know. and i dont know how to determine if you have the right combo either.

sorry.

tom w

origamitect · #6 05-12-2006, 10:26 AM

Tried the spacer on the slave last night. Worked for a minute, then - no grab at all. removed the slave alltogether. no grab still. Getting a loan and towing it to a mechanic. considering driving it into the mississippi.

Stevo · #7 05-12-2006, 07:27 PM

Quote:

Originally Posted by t walgamuth

yeah, i was wondering about that. they come in different thicknesses. why? i dont know. and i dont know how to determine if you have the right combo either.

sorry.

tom w

Determining which one goes where seems to be the trick. The early W123 T/O bearing is the thinner one. The thicker one, p/n 3151 069 131, is the later 240Ds. Theres about 3/16 difference in thickness. I have one of each in front of me.

Hope the car not at the bottom river

origamitect · #8 05-13-2006, 09:34 AM

I couldn't drive it into the mississippi - It won't move under its own power!

Hoping I haven't trashed the new clutch already and that getting a different t/o bearing will fix it. This has been the most expensive and frustrating thing I have ever dealt with in a car. By the time this is all done, I will have spent more than the original purchase price of $2000 on this transmission issue, not including the 2 week car rental. Goes into the mechanic on the 23rd. Will post results...

Stevo · #9 05-13-2006, 12:47 PM

I think your clutch will be OK. Their tough

If you have the part# of the bearing that Phil send, please post it. I thought the bearing would follow the tranny but not sure that would do it. It would be nice to sort this out for future referance. Hang in there, a year from now you will have forgotten all about the cash spent on your MB.

t walgamuth · #10 05-13-2006, 12:47 PM

if you cant get the clutch to engage, then i am guessing you have the thinner to bearing and need the thicker one. it is keeping the clutch pushed in too much. (the pedal, figuratively speaking)

tom w

origamitect · #11 05-27-2006, 12:52 AM

Had Ms Frankenbenz towed (thank goodness for Triple-A...I have gotten more than my money's worth on tows...) to a new indy. $95/hr shop rate

(which is $30/hr more than my last indy) but they were willing to deal with this hyper-customized assembly of parts. Gave them the whole spiel, discussed the options in-depth ("gosh, you know a lot about cars for a girl...") and left it nervously in their hands. They spent a day researching (fortunately not on my dime) and 7.8 shop hours later I had a working car. It turns out the pilot bearing that we had not-so-gently put in after 10 hours of honing had shattered, and bits of it were between everything. They removed all the pieces and parts, determined the flywheel and clutch plate were not scored enough to warrant replacement, got another pilot bearing and machined it down the 1/4mm that it needed to actually fit. Stuck everything back together, et voila! she runs beautifully. The good news is: my original conclusion about which release bearing to use was correct. I bought the other one just in case it was needed. So, to sum up - I used the release bearing that went with my flywheel and clutch (1983 240D), not the one that went to my transmission (115 series gearbox). I have to say, I was worried that after 2 weeks of driving a nice new Toyota Matrix rental car, that Frau Frankenbenz would seem old and junky. But, I have to say I really do prefer the smooth solid ride of the old Benz over the jittery light and tight ride of the Matrix. Plus I didn't have the anxiety of driving "someone elses car".

t walgamuth · #12 05-27-2006, 06:57 AM

wow!

good to hear you are back in the (benz) saddle. most folks would have given up long ago....hell, most wouldn't have ever thought to try it in the first place.

with your setup, if my experience with a 307 rear end and a stick is any guide, you will need to be careful with your takeoffs. the very high rear end ratio will stress your clutch, so just try to avoid dead stops as much as possible and when taking off try to avoid feeding the fuel in any more than necessary. premature clutch failure is to be avoided if possible. (obviously) with that setup you are almost taking off in second compared to a stock 240d gear ratio.

you should get 30 mpg on the highway though! which is pretty outstanding with nearly 30 year old technology.

tom w

origamitect · #13 05-27-2006, 09:58 AM

I adjusted my alda just before we did all this because I felt like I was smoking too much under any sort of load. Cleaned out the banjos and lines and installed the over-boost protection from the engine donor car. Leaned down the ALDA quite a bit and got down to a little puff on take-off only, and accidentally leaned it down a little more when I tightened the lock nut. Had stuff to do which kept me from adjusting it back up. So, starting from a dead stop is an exercise in patience anway.... Although I do intend on bumping it back up a little today - it's almost unsafe how slow it takes off. I will definitely be careful, I'm not really prone to dumping the clutch. I have found I really like the gearing of the 115 box much more than the old 123 box. It could be my imagination, but it feels like it has more range in all the gears, and that they're more linear, leaving 4th closer to a proper highway driving gear. Next project - lower oil cooler hose and front wheel bearings...(but not today!).

t walgamuth · #14 05-27-2006, 11:49 AM

yeah, i think the older boxes may have a lower first gear.

tom w