W114 not backing up anymore... Linkage diagram anyone?? 1976 280C lost reverse - PeachParts Mercedes-Benz Forum

VintageBenz.org · #1 09-29-2009, 12:55 PM

Summary of long winded ramblings below: I need a transmission linkage diagram for a W114 1976 280C.

Before I bought the 1976 280C I gave her the twice over. Took it for a test drive and backed up a few times, everything was working great. Then after driving it an hour and a half home to the hanger I parked it to begin the real evaluation the next day.

Well I got to the hanger and wanted to back it up so that I would have more room to look over the engine. No reverse….. When I went to back it up for the test drive the rear of the vehicle lifted quite a bit. More than my W126 lifts when I put that in reverse. I am pretty damn positive the linkage just needs to be adjusted. I also noticed an electronic box under the hood which had adjustments labeled with things such as “shift points” and other things that led me to believe it was a control box for the transmission.

Either way this is my first W114 and I don’t have a repair book for it yet and didn’t find anything online in regards to transmission linkage so any help would be greatly appreciated.

Regards,
Bryan Plaunt

samdon · #2 09-29-2009, 01:45 PM

Bryan,

Linkage may well be your issue but these old autoboxes have an externally adjustable reverse band. Check the linkage travel and be sure it OK first. If the bushings are good and things move into the tranny detents properly; you can pretty easily rule out the linkage. To test the linkage movement; disconnect the shift rod at the tranny shift lever. The last detent toward the read of the car is park. Put it in park manually. Then, place the interior shift lever in park. Gat back under the car and hold the shift rod up where it should mate with the tranny lever. If they line up just reconnect the rod and linkage travel is verified. If not; the rod is threaded and you need to adjust the length to match things up. I have dealt with these issues a number of times and have never found the actual linkage to be out of spec. The bushings are always in question but even with both of them completely absent; it should still click into each gear albeit with a good dose of slop.

Next step is to locate the reverse band adjustment on the front right side of the tranny. Just loosen the lock nut and use a 14mm(I think) spanner to tighten the adjustment bolt 1/4 turn. Tighten the lock nut being sure to secure the bolt while doing so. Test it out. If it works; you're done. If it still will not engage reverse or it does so slowly and with a clunk/jerk, give it another 1/4 turn. Continue the 1/4 turn and test routine until things are good.

Just enough is my rule. You can tighten it to the point where reverse will not disengage.

This is a free fix if you don't apply true value to your time. I find Benz wrenching relaxing most of the time and this is a rewarding repair if indeed a worn reverse band is your problem.

Sam

VintageBenz.org · #3 09-29-2009, 05:44 PM

Quote:

I find Benz wrenching relaxing most of the time and this is a rewarding repair if indeed a worn reverse band

As do I sir, as do I.

Looks like I will drive it up to the office where we have a lift one day next week. I just hope that this is the problem or else I'll have to push it off.

If all of the linkage looks good then what else do you speculate that it could be?

Thank you very much for the reply and advice. I will put it to good use!

Regards,
Bryan Plaunt

Tomguy · #4 09-29-2009, 09:23 PM

Did you check fluid level? In park when running and warm? Mine won't back up when it's a hair low and does have a slow leak. I know the band adjustment is off but it doesn't help when low.

meltedpanda · #5 09-30-2009, 09:40 AM

I suspect an easy linkage adjustment. I may be all the little rubber/plastic donuts bushings in between all the linkage adjustments are gone, ( as mentioned) this provides for a lot of slop and should be rectified, cheap at the dealers, have some handy

250 Coupe · #6 10-05-2009, 08:09 PM

I started a reply about the box and wanting pictures As I've never seen one in a 114 but something caught my eye. You say the suspension raises when in reverse. That leads me to think that the parking brake pads are stuck to the drums. They may be arranged in a way that will let the car move forward but not backward.

Michael

meltedpanda · #7 10-05-2009, 08:41 PM

good catch coup, did not see that , I wonder.....

VintageBenz.org · #8 10-06-2009, 01:04 AM

Well Michael I think you are on to something. It was nearly impossible to push it backwards even a few inches. I hate drum brakes but will have to atleast take the wheel off and have a look. ( Also have a cylinder leak on the right rear of the W111 I have to tend to so I might as well do them both.

However I know that I will have to do what Ron mentioned and replace bushings as now it doesn't raise the rear when placed in reverse which leads me to believe it's not even engaging.

I plan to help a friend with a customer's 61 Cadillac tomorrow and put the 280 on the lift to inspect the linkage. Wish me luck.

Thanks again for all of your help gentlemen.

JMURiz · #9 10-06-2009, 09:34 AM

My trans is a little 'loose' but it also raises up a little bit when reverse is engaged, but the parking brake isn't stuck....I thought it was just something it did.

Mine also will only start in Neutral...so maybe I have bigger trans issues.

meltedpanda · #10 10-06-2009, 11:49 AM

the parking brake is "inside" the hub, and separate from the disc brakes pads. Kinda cool as a safety feature, but PIA to service
Nathan - starting in neutral is probably your neutral saftey switch gone south or also bad linkage adjustment

250 Coupe · #11 10-07-2009, 12:34 PM

Quote:

Originally Posted by JMURiz

My trans is a little 'loose' but it also raises up a little bit when reverse is engaged, but the parking brake isn't stuck....I thought it was just something it did.

Mine also will only start in Neutral...so maybe I have bigger trans issues.

Independent suspensions will raise in reverse and lower in drive. That was the clue that lead me to thinking that the parking brakes were sticking. As meltedpanda says, they are inside the disc and probably very neglected. I've never serviced any of mine on the 4 MBs I've owned over the last 15 years. The cable on one side could be damaged and not releasing. It's less likely that a caliper is sticking since it will go forward, drum brakes tend to be "self assisting" (I forget the proper term) in one direction.

The neutral start could be worn bushings. I had to throw the 280C into park to get it to lock the trans and make the switch.

Michael