Can't Steer When I brake!! W108 250 S

[Loz]

Yeah, as bad as it sounds my front end locks up when I brake at normal road speeds. the wheel just won't budge. I dowsed the linkages with chain lube for a motorbike and it eased up a lot but it came back in a few days, another spray seems to have helpped but what am I looking at as the cause here? I don't want to just keep treating symptoms!

Cheers

Loz

[barry123400]

I am not sure but if both front brakes are refusing to release the master cylinder might be suspect. I guess you could jack up the front of the car and see if they are releasing.

You have to prove both front wheels are staying on before going there. Only one side could be as simple as a brake hose on that side. Usually it is the back brakes with a defective master cylinder. I do not know the w108 mechanically at all though.

[Loz]

Sorry I was not clear...

The steering wheel won't turn with the brakes applied. Its like braking pressure jams something in the steering set up...

trying to think of what forces could cause the steering rods to refuse to move normally.

I greased it again the other night and it came good again or at least much better... could it just be dried out joints and is there a better solution that spraying loads of chain lube in the arch...?

[Tomguy]

Only thing I can think of is the kingpins are so worn, when the rotational stress of braking hits them it causes them to seize.

Check your kingpins for any play. You may need new kingpins and bushings. If no play, at least disassemble them and flush the old grease out (it's probably more like tar by now) and re-assemble with fresh grease.

[MunichTaxi]

Is the steering box mount rusted, or missing any bolts?

[pj67coll]

Originally Posted by MunichTaxi

Is the steering box mount rusted, or missing any bolts?

I agree. Sounds like something in the steering is so loose that when you break it moves and jams against something else. No idea what that could be but to my knowledge there is no connection between the power steering system and the breaking system to my knowledge.

I'd check that steering box very closely.

- Peter.

[1christos1]

your issue sounds like the exact problem I would have had I not change my kingpins very recently. My mechanic showed mine and it was worn badly. Prices for these vary depeding where you go so do your research. You'll likely need the inner and outer bushings. I also needed a control arm because the thread was worn badly.

[Loz]

THanks guys...

turns out it was a strut type brace with double threaded caps and the internal threads were worn off completely so it was moving around...

Interesting that you mention power steering? I don't HAVE power steering? should I have it on a '67 250s?

it is a bugger to park I'll tell you that much going lock to lock. also there is 15-20 degrees of slack play in the steering wheel... related?

[pj67coll]

Originally Posted by Loz

THanks guys...

turns out it was a strut type brace with double threaded caps and the internal threads were worn off completely so it was moving around...

Interesting that you mention power steering? I don't HAVE power steering? should I have it on a '67 250s?

it is a bugger to park I'll tell you that much going lock to lock. also there is 15-20 degrees of slack play in the steering wheel... related?

Where are you? I suppose a 67 might not have had it but I'd be surprised. Glad you found the problem but that large amount of slack you mention is a warning sign. Check your steering gear box mounting points on the chassis box frame. Mine on my 71 280S was so loose that the steering shaft snapped on me, luckily when I was parking not driving at speed. There are three long mounting screws that should be torqued to spec and probably never have been in your car's entire life. In addition rust can cause the box section to decay as well.

Not sure about the non power steering car but there can be a lot of slack in the box of a power steering one when it get's old. Mine was just as bad as you are describing but I learned the hard way that on mine a large amount of the slack was caused by the box itself moving around because it was detaching from the disintegrating chassis. This is a safety issue. Get it checked.

- Peter.

[Loz]

I am in Korat, North East Thailand.

I had the whole system checked and came back ok now. just those things I mentioned. I did the N/S but D/S is on the way.

got preoccupied with driving lamps which I added this week.. night driving is now no longer a "safety issue" lol

Thanks for the great info.

[t walgamuth]

Try adjusting the steering box, they will adjust well even with a lot of miles on them. Non power steering does not surprise me at all.

[Mark DiSilvestro]

Originally Posted by Loz

THanks guys...

turns out it was a strut type brace with double threaded caps and the internal threads were worn off completely so it was moving around...

Interesting that you mention power steering? I don't HAVE power steering? should I have it on a '67 250s?

it is a bugger to park I'll tell you that much going lock to lock. also there is 15-20 degrees of slack play in the steering wheel... related?

Here in the US, by the late '60s, power steering may have been optional, but you'll be unlikeky to find an S-class Mercedes here without it.
Many years ago I bought a '72 W115 220 with automatic and AC, but MANUAL steering. A real pain to park, and the steeing also felt very queasy and sloppy at highway speeds. I assumed the sloppiness was due to an alignment problem as the car had at one time been in a bad front-end crash that wasn't completely repaired. But just before I sold it, I installed the power steering from a parts-car I had, and not only was parking now a pleasure, but that queasy feeling on the highway was also gone!

Happy Motoring, Mark

[pj67coll]

Originally Posted by Loz

I am in Korat, North East Thailand.

I had the whole system checked and came back ok now. just those things I mentioned. I did the N/S but D/S is on the way.

got preoccupied with driving lamps which I added this week.. night driving is now no longer a "safety issue" lol

Thanks for the great info.

Some pictures would be nice

- Peter.