W123 Very low clutch bite point on 5 speed manual

[Dan Dooling]

Hey guys

I have a 1983 300d 5 speed manual


I had a garage I always use change my clutch slave and master cylinders. Since then the biting point is really low almost instant. And the pedal feels very soft.


i asked them to bleed it again which they did and assured me that no air was in the system. But the problem remains.

Can anybody help with the cause of the problem please?


thanks


Dan

 

[John Laidlaw]

Doubt anyone knows what a clutch is on here

 

[john campbell]

A new clutch will be low to the floor until its done a few hundred miles.........

 

[EmilysDad]

A new clutch will be low to the floor until its done a few hundred miles.........

will it?

 

[john campbell]

Also you say its soft to press means its new as thats how they are supposed to be

 

[john campbell]

As the plate gets worn down the gap between the flywheel and pressure plate gets bigger thats why the bite point get high. Fitting a new clutch kit means less gap between the pressure plate and flywheel so the bite usually is low down untill its worn down a bit.

 

[ajlsl600]

Wots a manual ! I thought repair guide maybe ?

 

[john campbell]

Its one of those stick things .......

 

[Dan Dooling]

Apologies
It had a new clutch about 2 years ago. It’s recently had a new slave and master cylinder not clutch

 

[EmilysDad]

Apologies
It had a new clutch about 2 years ago. It’s recently had a new slave and master cylinder not clutch

and they were the correct parts? variation in bore of either would move the bite point (assuming they're all bled properly)

 

[Blobcat]

Doubt anyone knows what a clutch is on here

4 pedals, 1 for each leg...

 

[davidsl500]

There is a small possibility that the seal in the clutch master cylinder is displaced slightly so fluid is passing by it. This can happen on new master cylinders that aren't primed before fitting. There wouldn't be air in the system but the pedal would feel similar to as if there was. I would have expected some gear crunching as well though but it may just be on the edge so there is enough travel to disengage the clutch fully. I don't know whether your car has manual adjustment so that you can move the bite point.

 

[mattkh]

......... I don't know whether your car has manual adjustment so that you can move the bite point.

Generally, is there a manual adjustment system even on a hydraulic clutch?
If so, would it be at the pedal end or the master cylinder or elsewhere?
Thanks

 

[rifiki]

Agree with EmilysDad wrong master or slave cylinder or possibly an internal leak.
Check the part numbers.
Have a look at niemoller mercedes.de

 

[Doug1234]

A good clutch (new) will start to bite just off the floor and then need about another nearly 3 inches of pedal travel until it is fully engaged.
A worn out clutch will start to bite at nearly top of pedal travel and have a window of about 1 inch travel between bite point and engaged.
Driving with a worn clutch you can push the pedal down about half an inch and the engine revs start to rise, with a new clutch you have about an inch and a half more before revs rise as it starts to disengage.
Worn clutch is almost like an on/off switch and if badly worn then to get into reverse you often have to select 1st gear then drop it into reverse.

 

[davidsl500]

Generally, is there a manual adjustment system even on a hydraulic clutch?
If so, would it be at the pedal end or the master cylinder or elsewhere?
Thanks

Many automatically adjusted but some cars had adjustable pushrods on the slave cylinder end. The pushrod could be lengthened or shortened to move the bite position. Also, back in the "old" days the free play on the pedal could be adjusted by a bolt at the top of the pedal.

I don't know whether 123's had manual adjustment. I wonder whether the master and slave cylinders were actually changed or merely had service kits fitted - if so and the cylinders were worn that would explain the soft pedal due to fluid passing the seals.

 

[ajlsl600]

Push the rubber boots back,see any fluid ?

Unlikely, clutch release bearing not in its correct position,
In my view if still had air in system pedal would be softer till you displace that and pedal start to bite.yr sayin bites as soon as you try to depress pedal.

 

[DREAMER NO2]

Two types of slave cylinders were made for the W123 . So it may have the wrong cylinder fitted .The push rods are not the same length , one pushrod is longer than the other.. even though the cylinders are the same to look at.

 

[Dan Dooling]

Only just seen all the latest replies, thanks everybody, I need to look in to it a lot more and get it right.
More pressing issues at the moment though

the s124 has failed mot on the exhaust back box so that’s priority as it’s the missus every day car

 

[DREAMER NO2]

Dan you carry on my friend. you dont need to get flak from the little woman .