Really slow wipers - SLK 1997

[mercmatt]

Hi,

I have an SLK 230 1997 which had an MOT today. Imagine my delight when I got the call telling me that it was all A-OK!

However driving home tonight and went to wash the windscreen and the wipers were going at a snails pace on any setting (inter, norm & fast).

My first thoughts are that it is the motor but really I have no clue. Anyone suffered a similar fault and more to the point is it expensive? :-(

Any advice greatly appreciated

 

[television]

Hi,

I have an SLK 230 1997 which had an MOT today. Imagine my delight when I got the call telling me that it was all A-OK!

However driving home tonight and went to wash the windscreen and the wipers were going at a snails pace on any setting (inter, norm & fast).

My first thoughts are that it is the motor but really I have no clue. Anyone suffered a similar fault and more to the point is it expensive? :-(

Any advice greatly appreciated

Do you have one single wiper.

Malcolm

 

[mercmatt]

Hi Malcolm,

It does not have the Mercedes trade-mark single wiper, it is two wipers like a 'normal' car.

 

[television]

Hi Malcolm,

It does not have the Mercedes trade-mark single wiper, it is two wipers like a 'normal' car.

Then if they are both going slow it will not be the motors, got to think about this

Malcolm

 

[jberks]

Not sure Malcolm. Aren't the 2 wipers run off a single motor with an interconnecting bar?
Does the speed change at all, depending on the switch setting? I'd expect the speed to increase a little on fast if the motor is duff, though I don't know exactly how it's regulated so this may be wrong.

 

[television]

Not sure Malcolm. Aren't the 2 wipers run off a single motor with an interconnecting bar?
Does the speed change at all, depending on the switch setting? I'd expect the speed to increase a little on fast if the motor is duff, though I don't know exactly how it's regulated so this may be wrong.

You are dead right, its me not thinking clearly, too the point where my answer was stupid , you cant have 2 motors, the fault is nearly always the linkage going tight, or what did they do when they lifted the arms to check the blades on the MOT. some of the modern lubricants are very good,esp; the ones that contain Silicon and PTFE as used on router cutters.

If you want any help in accessing the wipers, please ask.

malcolm

 

[angus falconer]

I have seen several threads on C classes suffering a similar problem. On those the remedy was to lube the linkages. If you don't you burn out the wiper motor (expensive)

Do an advanced search and you should find something.

 

[television]

I have seen several threads on C classes suffering a similar problem. On those the remedy was to lube the linkages. If you don't you burn out the wiper motor (expensive)

Do an advanced search and you should find something.

Hi Angus, I should have said, don't use till fixed.

Malcolm

 

[mercmatt]

Right ... So probably not the motor then!

I need to lubricate the linkages? How do I go about doing this (where are they and what am I looking for to put the lubricant on?). I am not afraid to attempt fixing things, however I need to be 'armed' with the knowledge!

Also just to confirm they are the same speed on all settings and that speed is very very slow. Is there a 'recommended' lubricant or can anyone make some suggestions?

One other point to raise is that they have not got slower and slower, it has gone from fine, to bad in one fell swoop ... hmmmm?

Thanks for all your help on this ... off to pray for a few days of sunshine!

 

[television]

Right ... So probably not the motor then!

I need to lubricate the linkages? How do I go about doing this (where are they and what am I looking for to put the lubricant on?). I am not afraid to attempt fixing things, however I need to be 'armed' with the knowledge!

Also just to confirm they are the same speed on all settings and that speed is very very slow. Is there a 'recommended' lubricant or can anyone make some suggestions?

One other point to raise is that they have not got slower and slower, it has gone from fine, to bad in one fell swoop ... hmmmm?

Thanks for all your help on this ... off to pray for a few days of sunshine!

I will put up some more info tonight on how to get to them.

malcolm

 

[mercmatt]

Thanks Malcolm ... I appreciate your help and time on this.

Matt

 

[jberks]

All,
given that it suddenly went slow and that the speed remains unchanged even when on fast where theoretically more current is going to the motor, I can't help feeling that the problem is more electrical than mechanical.
The kind of things that come to mind would be a poor earth but what I don't know (though I suspect Malcolm will be able to find out) is how the speed is governed. Is it a simple resistor to the motor or is there some form of fancy regulator involved?

 

[television]

All,
given that it suddenly went slow and that the speed remains unchanged even when on fast where theoretically more current is going to the motor, I can't help feeling that the problem is more electrical than mechanical.
The kind of things that come to mind would be a poor earth but what I don't know (though I suspect Malcolm will be able to find out) is how the speed is governed. Is it a simple resistor to the motor or is there some form of fancy regulator involved?

The motors have double wound field coils for the speeds, not that easy to control DC motors with voltage alone.

malcolm

 

[mercmatt]

Thank you everyone for your insights. So we have narrowed it down to the following?

Linkages needing lubricant
New motor needed
Bad earth connection

Any ideas on how to go about testing each of these theories and in which order to do it!

Thanks

 

[Blobcat]

You could lift the wipers off of the screen, then switch the wipers on, stand outside and listen to them. (I'm assuming that your wipers will clear the bonnet with them lifted). Do it with the engine off.

 

[television]

Your is a 170 with that year I think, you can see the linkage under the bonnet. if you removed the center nut on the end of the wiper this would anable you to check how tight the linkage is, it is all controlled by the multi function relay, just be lifting the blades off the screen you should be able to feel how tight the linkage is by testing for backlash.

Malcolm

 

[mercmatt]

OK, thanks, I will try tomorrow. What am I listening for? I guess the motor will sound laboured if the linkage is too tight.

Had a quick look when I got home. Can't see anything, all hidden under a plastic cover, did not look to hard to remove tho ... famous last words!!

 

[television]

OK, thanks, I will try tomorrow. What am I listening for? I guess the motor will sound laboured if the linkage is too tight.

Had a quick look when I got home. Can't see anything, all hidden under a plastic cover, did not look to hard to remove tho ... famous last words!!

Lift the blades off the screen, take hold of the one furthest from the motor, move the arm slightly backwards and forwards, it should have a little free play before it moves the other arm and blade, if it is dead tight then you know that it is that. Its very hard to describe this action, those with mechanical minds will understand what I mean. be carefull what you take off or do,otherwise you will lose the parking position.

malcolm

 

[mercmatt]

All,

I ended up taking the car to my guy that does my MOT's at lunch. He kindly had one of his guys take a look and it appears the linkage has ceased up. They tried to lubricate it, however it did not make a difference so they have ordered me a new linkage from MB - £25 (cheaper than a VW golf by all accounts which they had fixed a similar problem on a few weeks ago!!)

They will fit it Monday for £10! So overall not bad ... lets just hope the motor has not been damaged whilst I have been using it to show the problem!

Thanks to everyone for their help and advice.

Matt

 

[panason1c]

All,

I ended up taking the car to my guy that does my MOT's at lunch. He kindly had one of his guys take a look and it appears the linkage has ceased up. They tried to lubricate it, however it did not make a difference so they have ordered me a new linkage from MB - £25 (cheaper than a VW golf by all accounts which they had fixed a similar problem on a few weeks ago!!)

They will fit it Monday for £10! So overall not bad ... lets just hope the motor has not been damaged whilst I have been using it to show the problem!

Thanks to everyone for their help and advice.

Matt

I would be surprised if the reason for your slow wipers is a seized linkage, if that was the case i would still expect to see a corresponding change of wiper sweep speed from the 'slow' to 'fast' switch position....it should be relatively simple to disconnect the motor from the linkage and then to see if the motor speed steps up/down when switched which, if it doesn't, would negate the seized linkage theory. Anyway, surely a linkage would seize steadily over a period of time and you would notice the wipers GRADUALLY going slower and slower....not 'ok' one day and seized the next!....I would investigate some more before i paid for a new linkage when i'm sure you own linkaged could be removed and lubricated.

You mentioned that this was a sudden occurence after collecting your car from an MOT test........One possible scenario is........When the tester operated your wipers he could have been distracted and forgot to turn them off and left them running on a dry screen, resulting in a damaged motor??