Removing abs from 85 sd - Page 2 - PeachParts Mercedes-Benz Forum

mach0415 · #16 08-18-2010, 07:02 AM

Look for cracked tone rings, as well as dirt and corrosion. They will be hairline cracks, so look very carefully. I pulled my relay and I like it that way. No compromised stops here in the south. Indiana and snow may be a different story, though.

t walgamuth · #17 08-18-2010, 07:18 AM

I like having it on my Mrs's car but don't really feel the need for it on mine. The benzes are very well balanced and it is fairly easy to get good performance out of the brakes for me.

t walgamuth · #18 04-13-2011, 07:04 AM

I think the brakes are dragging a little in front. Lots of brake dust hotish rotors and poor fuel economy.

Can I just pull the whole system and go back to basic brakes?

compu_85 · #19 04-13-2011, 07:21 AM

ABS will not cause the brakes to drag... unless there is something very wrong with the valve unit, but I would think you would notice that in reduced braking force to the front too. And you'd have to have multiple stuck valves for both front brakes to be holding on.

Now it could be a problem with the master sticking? Both fronts use the same section of the master cylinder.

If you pull the fuse on Bosch ABS2 you go back to normal non ABS brakes, unlike some other / newer systems.

I still bet good money you stop quicker with ABS on the dry then without. I'll test it once Roy gets my car going again.

-J

t walgamuth · #20 04-13-2011, 10:10 AM

Will the fuse be labeled ABS?

300sdToronto · #21 04-13-2011, 01:35 PM

I have an 83 300SD and goodness, I wish I had an ABS unit to repair!

There have been a few icy and snowy approaches to hairpins going downhill where ABS would have been really, really nice.

I need to search the posts on limited slip diffs as well as one of those would be handy in snow country....

RL

compu_85 · #22 04-13-2011, 04:23 PM

Quote:

Originally Posted by t walgamuth

Will the fuse be labeled ABS?

I'd have to look in the service manual. There will be a control relay for the whole system. I don't know where that lives on the W126. You could also just unplug the computer, it's the long box up by the wipers with the long connector on it. Cover it up though, you don't want water getting into the plug or the control unit.

But like I said, i'm 98% sure the abs system is not the source of your dragging brakes, and if it is working properly you're better off with it.

-Jason

vstech · #23 04-13-2011, 04:31 PM

my experience with abs is beer makes them go away... as do cookies! but you get a spare tire to replace them with!

t walgamuth · #24 10-16-2011, 02:50 PM

My SD spent most of the summer sitting at one repair shop or the other. I am very interested in getting it sorted now. We took it on a trip a week or so ago and I decided I had a brake dragging.

I looked and the pads were low so I went to put on new pads and we found one of the calipers had a stuck piston. I then put a new caliper on. Now it won't bleed for me. The pedal sticks about halfway down and when I try to pump to bleed it it won't come back up without being pulled and then it feels as if it has glue in the MC instead of brake fluid.

Roy says I can ignore the ABS unit when bleeding the brakes, fail safe is that the fluid will simply pass through. What is in there? Is there rubber seals that can go bad or simple metal pistons with no seals to fail?

Any words of wisdom?

compu_85 · #25 10-16-2011, 02:54 PM

There are spool valves and a pump inside the abs unit. I believe they have o-rings on them. Unlike some other ABS system there is no special procedure for bleeding it.

engatwork · #26 10-16-2011, 03:25 PM

Quote:

Roy says I can ignore the ABS unit when bleeding the brakes, fail safe is that the fluid will simply pass through. What is in there? Is there rubber seals that can go bad or simple metal pistons with no seals to fail?

Roy is correct.

In my opinion, the biggest part to remove (if you get rid of it) would be the ABS unit under the hood. The issue is going to be getting all the plumbing back together when the module is removed.

On another note I drove the first motorcycle I have ever ridden with ABS the other day and it was kinda neat being able to grab a bunch of brake on sand and pine straw and not busting my arse.

t walgamuth · #27 10-16-2011, 03:34 PM

What about my pedal sticking halfway down? Any ideas on that?

engatwork · #28 10-16-2011, 03:38 PM

I'm not sure about that Tom.

The replacement of the caliper indicates to me that the brake fluid did not get changed like it should have been done (every 2 years) so there could possibly be some other issues but I doubt if the abs module is causing it. How nasty does the fluid look in the reservoir? Have you tried to see if you get bleed/flow to all the calipers now?

compu_85 · #29 10-16-2011, 05:07 PM

It's possible a stuck valve in the ABS unit could cause a low pedal. An easy way to test would be to block off the connections at the ABS unit going to the wheels and see if the pedal is still mushy. VW sells a plug which is perfect for this, if you like I can dig up the part number.

-J

Junkman · #30 10-16-2011, 10:00 PM

Be careful removing and installing the brake lines that go to the ABS unit. They cross thread very easily and the unit will need to be replaced. You will need to replace brake lines with some from a non-ABS car or fabricate some lines to patch where the ABS unit was if you decide to remove it. It is much easier to repair or disconnect the electrical plug.