installing ABS in non-ABS W116,possible?

[Takernz_30]

hello,

I've found an ABS module from 2nd gen. W126. before buying, can I install it in my non-ABS equipped '78 280S? 1978 was the year when the ABS was born?

[Mike D]

Why?

Thou shalt obey always the 1st law of mechanics and that rule is, "Objects in an operating condition shall not be disturbed or improved upon".

If it ain't broke, don't fix it!

[cth350]

Don't forget that beyond the hydraulic operation of the brakes, there is an electrical wire harness, brain box and wheel sensor setup to adapt.

The first mercedes with ABS was the W116 6.9 cars of the late 79, early 80 vintage (as optional equipment).

Personally, I'd stick with the basic 4-wheel disk brakes. They're pretty good under all circumstances and are certainly better than anything US made with rear drums in the same time period.

-CTH

[Skippy]

It's possible to convert a non-ABS car to ABS, but you will need more than the ABS module itself. You will need wheel speed sensors, wiring, more and different hard lines than what's on there now, etc.

IMO, it's not worth the effort to convert when you can just learn threshold braking, especially if the ABS system in question is going to be of questionable quality, as a homemade one probably will. Drive an early 90's ABS equipped Cadillac to get an idea of what I'm talking about by "questionable ABS".

[mercmad6.3]

it's pretty simple to swap over actually,there are two extra brake lines to the master cylinder and ABS pump and you need the loom to connect to the module (ECU) from the pump and to the power,including the OVP relay ( silver box with red fuse holder on top. You need the W126 front disc rotors with the pick ups for the ABS. there are two sets of wires on the front discs,one is the pad sensor the other the ABS.
it all unplugs so it comes off separately. The W126 Rotors fit straight onto the W116.
There is a single line from the ABS module running through the car to a dual terminal block under the rear seat. remove the cable and disconnect it without bust ing it. Now the hard part. the rear wheel sensor is in the diff housing so you will need to swap diff heads,or if you want to keep the same ratio ,swap the housing so you can retain the sensor.
The cable locations speak for them selves.
The easiest way to hook up the ABS in a W116 is to have the donor W126 beside you so you can disconnect the brake lines etc and fit them to the victim... The bracket for the ABS must be welded into the W116 to secure the pump .
All in,it's about 2-3 days work from go to whoa . ABS is great in wet or slippery conditions allowing the driver to brake hard with out the car going all over the place.

[GregoryV022]

Originally Posted by mercmad6.3

it's pretty simple to swap over actually,there are two extra brake lines to the master cylinder and ABS pump and you need the loom to connect to the module (ECU) from the pump and to the power,including the OVP relay ( silver box with red fuse holder on top. You need the W126 front disc rotors with the pick ups for the ABS. there are two sets of wires on the front discs,one is the pad sensor the other the ABS.
it all unplugs so it comes off separately. The W126 Rotors fit straight onto the W116.
There is a single line from the ABS module running through the car to a dual terminal block under the rear seat. remove the cable and disconnect it without bust ing it. Now the hard part. the rear wheel sensor is in the diff housing so you will need to swap diff heads,or if you want to keep the same ratio ,swap the housing so you can retain the sensor.
The cable locations speak for them selves.
The easiest way to hook up the ABS in a W116 is to have the donor W126 beside you so you can disconnect the brake lines etc and fit them to the victim... The bracket for the ABS must be welded into the W116 to secure the pump .
All in,it's about 2-3 days work from go to whoa . ABS is great in wet or slippery conditions allowing the driver to brake hard with out the car going all over the place.

although it is possible, its not worth it. ive driven a vehicle with, "questionable ABS", not a good idea.

plus, non ABS vehicles can be fun to drive in certain conditions.

aka 360 degree spins.

[mercmad6.3]

I guess if the car in question was a 280SE or 350SE and a junker,maybe so,but i have been helping someone install ABS AND yaw control into a 220SE coupe.
Not so difficult but time consuming as sensors have gto be installed on the axles (all four) to operate the suspension computor and brakes. it should make for a nice driver when finished.
Driving ABS is to enable the car to keep heading in the desired direction,and not allow understeer under heavy braking as happens on non ABS cars. Once that point is understood then it becomes clearer as to why it is such a good idea.

[Takernz_30]

thanks for the input guys but I'm scrapping that idea, anyway I bought myself a used brake booster(from another W116) for my '78 280S b/c the original one is now a junk,(hissing sound when applying the brakes and erratic idle even the carbs are good),before buying the booster, I checked the big yellow vacuum line for cracks and 1-way valve by sucking like other guys did in the forum, it was good, disconnected and checked the MC and the back side was dry meaning no leaks into the booster, I changed the big seal ring bet. the MC and booster w/ a VITON one but a little fatter than the original for better sealing, and lastly I had to change all brake hoses and rebuild both front calipers. The used booster is now installed and filled with my usual CASTROL DOT4 fluid and did a 1-man bleeding and start the engine and I got firmer brakes and lowered the idle a little bit and no hissing sound when applying the brakes. Whew, what a work in a day!

[Takernz_30]

continuation of booster installation folks!