The car is a 1987 420SEL. I have: had the front rotors turned, replaced front pads, replace front rubber hoses, and replaced the front calipers with professionally rebuilt ones. What else could cause it to pull? It is VERY sharp. You have to turn the wheel quite a ways to the right to keep from doing a 180! Both front wheels seem to have equal heat/dust on the rims after driving. Could one piston being bad in the RR caliper cause it to pull very bad? It does it even on light braking, so I figured it would definitely be in the front.
Could a problem like this be an ABS thing? The light isn't on, and it seems to work whenever it's needed. This problem seemed to just start up one day and has gotten slowly worse over time. I want to try and disable the ABS, but I coudn't find a fuse, and I didn't know what relay it is. I didn't think it would help, but I just wanted to try and knock the off the list of possibilities, since I'm running out of other things to replace.
Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Have you checked tire pressure? Have you had the alignment checked?

Sixto
95 S420
87 300SDL

The car's had an allignment, and the tires are about 3,000 miles old. I don't think one of thopse even being slightly off could cause it to pull as bad as it is.
Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Master cylinder (one of 2 systems failing), deteriorated front subframe mounts, worn idler arm bushes, and lots of other stuff you may have checked but not mentioned.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

you may have tried this already, but have you switched the front wheels? My car was pulling to the right even after a proper alignment and various components replaced. Switched the fronts over and boom- straight tracking. The car still follows the road camber but I hear this is a normal trait with Merc steering.

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1993 320TE M104
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past:

1983 230E W123 M102
1994 E300D S124 OM606 (x2)
1967 250SE W108 M129
1972 280se 3.5 W108 M116
1980 280SE W116 M110
1980 350SE W116 M116
1992 300E W124 M103
1994 E280 W124 M104
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"music and women I cannot but give way to, whatever my business" -Pepys

Its very difficult to help answer a question like this when anything in the front end may cause a pull and even some things in the rear end may cause your car to drive crooked. Sometimes the problems are related.

Has the front end been checked for worn parts? Pushing and pulling the tire at 12 & 6, 3 & 9 o'clock ? Have the bushings and upper controls been checked for wear? Have the tires been swapped side to side (tires can pull very badly) ?

Throwing parts at a problem is frustrating.

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Brian Toscano

I agree with brian it may have nothing to do with your brakes. My tie rods are worn and I pull to the right when braking, I am having then changed next week.

Tire pressure difference will surprise you especially with a Benz. Mine is so sensative that a 1 pound difference on either side will cause the car to drift. Eleminate that possiblity by making sure the pressure is equal on both sides and at the right setting.

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89 190E
2.6L
Arctic white
Grey leather
Sunroof
Pirelli P400 rubber
Smoked corners

First, keep in mind that if the car pulls to the right, then the left rear brake may be the problem, or if it pulls left it could be the right rear brake. Also remember that it may not be a problem with one brake not working, but another working too good.
A trick I have been using for years is find a dirt road, hard dirt field, grass field, etc. Then do a semi-panic stop on one of these serfaces. After you stop, get out and look at the tire tracks left in the dirt. An outside observer also helps. Look for signs of brakes not enguaging at the same time, or not at all, or possibly one brake locked up sooner than the rest of them.
I think you get the idea. When you find one brake not working like the others, you know where to start.

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84 500 SEL (307,xxx miles)

Bad bushings on the rear controls arms does this too -- however, it will steer the OTHER way on acceleration.

I'd take a look at the track rod bushings. If one is bad, that wheel will move back on braking and cause steering geometry changes.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

We have checked the front-end for worn parts. Every once in awhile I hear a slight clunk noise when hitting a pot hole at slow speeds, so I think it will need ball joints. Everything else looked pretty good actually. Idler arm, tie-rods, etc were really good. If it were the subframe mounts would the car really pull really bad?
Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Sbourg, I thought the master cylinder is dual-circuit? It controls front and back, not left to right. Are there any kind of proportioning valves in the front? When we bled the brakes, each side seemed to have equal rpessure coming out of the screw. I know that's not a very scientific statement. Are you saying I should rotate them front-back, or left-right?
Thanks Again
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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David:

Clunk on bumps is a bad track rod to body bushing.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Could this be a master cylinder or perhaps an ABD pump? I wouldn't think that this would have anything to do with that system though, becasue when ABS systems are down, brakes work fine, just not ABS.
Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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Sounds to me like a guide rod mount. Visual inspection of bushes is difficult, often they look fine but when you take them apart it is obvious they are very worn.

Check tire pressures, rotate wheels and get another alignment if it hasn't been done since the problem was occuring.

If you can't diagnose this further then a trip to an experienced mech is in order.

Matt.