Trying to get use to my FIRST 280SE so I need help. - PeachParts Mercedes-Benz Forum

purpleGORILLA · #1 03-01-2007, 11:02 AM

So I have been driving this car around a bit since I got it. Took it on the freeway and cruise at 70-80mph couple of times. Noticed the temp climbs up a little bit but goes back down if I slow down. Don't really know what is the normal temp on the gauge. I am just estimate from the bottom number on the gauge showing as 175 , and next one is 185 to 195 and top is 210.

Here are two things I need help with.
1. How to get the radio out and speaker grill out. I only found one speaker grill in the middle but don't want to break it. Should I upgrade to a modern radio for my personal use and put the becker back if I decide to sell it(not working, only lights come on).

2. There is this loud thunking sound that I hear everytime I come to a near stop. This makes with wether I slow down quickly or slowly. It sounds like it is coming from the rear end but I can't figure out how it would make sound. From the purchase order (original), it shows the owner bought Limited Slip Differential. I didn't think the LSD would make a loud sound when you come to a stop, I have an aftermarket LSD in a nissan 240sx that would only make loud thunking sounds when I turn sharply and slowly, but never to a stop. Is the mercedes LSD a viscous or gear typed?

Is there a book where it can show how to restore this particular model. I saw one book on Ebay but not sure how informative it is.

Thomas Webb · #2 03-01-2007, 11:26 AM

I have a '69 280SE 6cyl w/four speed manual and limited slip. I didn't catch which engine you have. My car rarely goes above 180 degrees - even in Summer. I've seen it creep towards 200 - but only after a long blast on the interstate.

My limited slip doesn't clunk. I would suspect your trailing arm bushings or the differential mount itself - how is it over low speed bumps/railroad tracks?

The best book I have found for these older Mercedes is "Glenn's Mercedes Repair" which is found on Amazon. It's the best $14 you'll ever spend on your Benz. The book as pictured has a 190SL on the cover in a black and white illustration. It's far better than the $35 Haynes manual I bought, and covers everything from setting up the fuel injection correctly, to ignition timing, etc. I don't believe it covers the 3.5 or 4.5 V8s, but the 6.3 is actually covered. It includes many tables and "at a glance" specifications for tune-ups, etc.

Happy Motoring,

Tom Webb

purpleGORILLA · #3 03-01-2007, 11:38 AM

Sorry, it is an inline six with automatic tranny. I noticed that it makes the thumping sound when it downshift..Especially at the last downshift..

Thomas Webb · #4 03-01-2007, 12:15 PM

Purple G,

Hopefully someone will reply who owns an auto'box from your vintage. I have heard from a number (a lot, actually) of people that the 'Benz auto'boxes were very clunky-shifting, even when new. It was for this reason that the four-speed manuals were available in this type of car long after most luxury manufacturers stopped offering them.

Check your U-joints and the center-bearing too. These are safety critical, and will cause clunking in shifting or changing direction

If you don't already have them, get a copies of "Mercedes-Benz Saloons" by Lawarence Meredith, and "Original Mercedes-Benz coupes, cabriolets, & V8 sedans" by Tim Slade. Both books have lots of good photos and text about what's under your car.

Tom Webb

sjefke · #5 03-01-2007, 05:13 PM

To get speaker grille out, look for small black screws in the speaker grille and remove them.

To get the radio out, remove the black knobs by pulling on them away from the radio. Next remove the trebble adjust and other black lever under each know (if you have any). You will see hex nuts under them. Remove these. Now you have to remove the face plate. The chrome edge snaps onto the body of the main radio, so carefully work your way around the edges to get it loose. Once the edge is off, the face plate follows immediately. Once the face plate is gone, you will see a flathead screw in brackets on each side holding the radio clamped to the dashface. Loosen them so the clamps can slide up and down easily and have play. Theys should be in the middle position and sliding down will free top of radio, pull out radio partly, and slide bracket opposite side to remove other side of radio. If radio is attached to a bracket in the rear, loosen nut and undo wiring.

I had a modern radio in my MB (a HONDA radio!), but already stereo speakers in the footwell, so put a Becker Mexico in. Great sound.

cth350 · #6 03-01-2007, 07:06 PM

There are two heavy rubber donuts that mount the trailing arms to the car. There is also a center mount on the differential in the trunk. Lastly, a large bolt with some rubber spacers that adjust where the center sits on the rear.

I suspect one or more of those need replacing for that noise.

Or, perhaps it doesn't come from the rear but instead is from the center. That would mean the transmission mount, the center bearing on the drive shaft or one of the two rubber couplers on each end of the drive shaft.

See ifyou can get two friends to stand far enough apart for you to drive in between them and stop. See if they agree on the location of the noise.

-CTH

Blue 72 250 · #7 03-01-2007, 08:40 PM

temp issue may indicate a bad thermostat. Easy fix. There should be no change in temp when running this time of year. If she takes a long time to come up to temp that would be a sign of stuck open.

The radiator may be full of crap also. If you drain the cooling system and find any floaters, or if there is a sign of weepage around the top of the radiator it would be a good idea to have it boiled out at a local shop. Cooling system issues are easy to fix this time of year, but if you wait until an overheating issue shows this summer, then be prepared to stand in line at the radiator shop. For $80 that old copper core will be flawless.

t walgamuth · #8 03-01-2007, 09:48 PM

yeah, i suspect a dirty radiator too. could be external dirt plugging the fins or internal.

it is easy to remove and on one that old should be all brass so can be dipped to clean it.

tom w

68_280SE · #9 03-02-2007, 08:50 AM

My 68 280SE also clunks from the right rear when the trans downshifts. I have replaced all of the rubber bushings, mounts and spring pads in the rear suspension, new shocks, rebuilt drive shaft, new flex disk, new trans and engine mounts. After all of this the car still lightly clunks when the trans down shifts, but the car rides and handles better than it every had before.

When i first got my car the temperature gauge would climb pretty high when I was driving 70+MPH. I finally had to have the radiator boiled out to solve that problem.

It good to see another Atlanta person with such nice 108. Check out this post to see some pictures of my car. http://www.peachparts.com/shopforum/showthread.php?t=151489

John

purpleGORILLA · #10 03-02-2007, 01:56 PM

Thanks everyone for the input. I will try to put the car on the lift as soon as the 240sx I am working on gets its tranny back on...

John, if you don't mind. I might have to come and see your car one day and let you test drive my car for your input..From the pictures, it looks very nice.