transmission slipping in really hot weather - Page 2 - PeachParts Mercedes-Benz Forum

cooljjay · #16 10-10-2015, 08:00 PM

Quote:

Originally Posted by Frank Reiner

And now, a few overly excited, ill mannered words from Cassandra:

Absolutely false; utter rubbish.

Really? Well it happened to me....And the hydraulics for the clutch are driven from the brake fluid reservoir...If....the clutch or master cylinder is leaking, it will run the brake fluid out of the reservoir....Thus adding air into the brake system and thus no brakes....And yes....I know "technically" its suppose to starve the clutch before the brakes...

ambush276 · #17 10-10-2015, 08:11 PM

Brake fluid is at full. Has been for over a year when i did my last brake flush.

mannys9130 · #18 10-10-2015, 11:20 PM

The clutch hydraulics share ONLY the reservoir with the brake hydraulics. One will not cause the other to fail.

As well, the hydraulics are NOT THE ISSUE.

Fluid will make no difference. You are either in gear or not, there is no in between with a standard transmission.

A clutch CAN last only 60k miles if:
The flywheel wasn't resurfaced at last clutch job
Low quality aftermarket clutch was used
Improper bedding in period observed after clutch replacement
Rear main leak contaminating clutch disk with oil.
A warped pressure plate caused by harsh high speed downshifts
Downright abuse caused by improper driving technique and accelerated wear on the clutch disk.
Broken pressure plate finger spring from faulty metallurgy.

If the car is slipping in gear, it's the clutch. Inspect it and go from there. You mention having new oil for the trans that you'll save till later. I hope it's Dexron III automatic transmission fluid. That's what these cars call for in their manual transmissions.

The clutch job shouldn't be that hard on a 240D. The worst part is letting the trans come safely off the car and putting it back up. I hope you can bench press 100 pounds and hold it.

cooljjay · #19 10-10-2015, 11:41 PM

Quote:

Originally Posted by mannys9130

The clutch hydraulics share ONLY the reservoir with the brake hydraulics. One will not cause the other to fail.

You know, I really wish I knew where you guys get your brake fluid fairies at....because this fairy sure the helll seemed to have an issue, when his slave clutch was leaking and not knowing it, causing the brake fluid to leak out of the reservoir....Since I was on an incline...It caused air to get into the reservoir thus I had no clutch nor brakes...

I am not getting......why certain people always have to debate every god darn thing....shesh just yesterday I had a women debating why I was buying a pumpkin at the grocery store....

away....This tart needs some S'mores...

mannys9130 · #20 10-11-2015, 01:30 AM

This fairy doesn't understand how you lost the clutch when the feed line to the clutch master also acts as a reservoir. If your slave was leaking, it probably held no pressure and that's what caused the clutch to not disengage. This fairy replaced the entire clutch system in his car and has an intimate knowledge of it.

Some things are debatable and others are fact.

This still doesn't change the fact that hydraulics aren't the issue. If his hydraulics were totally inoperable, he'd be stalling the engine as he came to a stop, not having trouble getting up to speed...

cooljjay · #21 10-11-2015, 02:37 AM

Quote:

Originally Posted by mannys9130

This fairy doesn't understand how you lost the clutch when the feed line to the clutch master also acts as a reservoir. If your slave was leaking, it probably held no pressure and that's what caused the clutch to not disengage. This fairy replaced the entire clutch system in his car and has an intimate knowledge of it.

Really? I must not have a mercedes then....All these years I've been working on what I thought was a mercedes and turns out its a Pirus

What is that line that runs to the clutch master like 10mm...how the heck does that act as a Reservoir....

Nope, slave lost all the fluid from bad rubber seals....thus the clutch failed to engage because there was no brake fluid...Can't run on air...but again I have some other strange make of car....damn these Germans...

Oh how I wish people would just admit defeat....

mannys9130 · #22 10-11-2015, 02:47 AM

#38 in the diagram you posted above.

The master is full of fluid. When you push the pedal to disengage the clutch, that fluid is pushed to the slave and the plunger covers the hole for the reservoir. When you release the pedal to engage the clutch, the pressure plate pushes the slave back and the fluid is pushed back into the master. If there are no leaks, there is no movement of fluid whatsoever. That line is a good foot long. It has enough fluid so that even if the reservoir is totally dry, you won't suck air.

Your slave FAILED which means it wasn't operating normally. It leaked all of the fluid out. The slave is on the bottom. This thing called gravity caused the fluid from the slave to drain as well as all the fluid in the hard line up until it met a curve that was lower than the bend. Once the slave is empty, of course it won't work. You are describing a totally different scenario here.

What I'm saying is, with a perfectly good master and slave that do not leak, an empty brake fluid reservoir will not cause the clutch to lose pressure. Plain and simple. I'm not understanding how you fail to see that. I share your wish.

cooljjay · #23 10-11-2015, 03:06 AM

Quote:

Originally Posted by mannys9130

Your slave FAILED which means it wasn't operating normally. It leaked all of the fluid out. The slave is on the bottom. This thing called gravity caused the fluid from the slave to drain as well as all the fluid in the hard line up until it met a curve that was lower than the bend. Once the slave is empty, of course it won't work. You are describing a totally different scenario here.

What I'm saying is, with a perfectly good master and slave that do not leak, an empty brake fluid reservoir will not cause the clutch to lose pressure. Plain and simple. I'm not understanding how you fail to see that. I share your wish.

Wheres that head palm smiley when you need it....

Stretch · #24 10-11-2015, 04:09 AM

All this talk about fairies and slaves is freaking me out!

Back to the OP=>

Quote:

Originally Posted by ambush276

...

The question i have i guess is... is putting in a new clutch a DIY or is that something i should take to a shop.

...

never have replaced a clutch in a car... but was curious what your thoughts were?

-- Thanks

Please note:

The problem you described in the first post where the gear selection was difficult is often due to a poorly bled clutch hydraulic system. (Can also be due to shifter bushings or a worn shifter)

The "revs going higher" but the car not accelerating - clutch slipping - could be due to a worn clutch. But it could also be due to a sticking slave cylinder.

The point made previously that a slave cylinder could be causing your trouble is in my opinion worth checking out.

The link I posted before shows how to do this job. It is not necessarily an easy job - bleeding the clutch hydraulics is likely to be exceedingly frustrating the first time you do it. But this is probably easier than removing the gearbox and fitting a clutch for a first time DIYer especially if you do not have a lift.

If you do not have a lift and you have not done this job before the chance of damaging the gearbox on fitting and / or removal is quite high - I would consider the other option first.

ambush276 · #25 10-13-2015, 07:50 PM

ok i have another update. Just did a long drive ~400 miles. No slipping in the clutch at all on the drive. Granted i was only going between 3 and 4th when going up and down hills.. but overall that was really smooth.

I eventaully pulled over into a town for a break. Then after about 15 mins in town it started to slip again. I stopped to eat something for 30 mins.. came back out and all was well. Shifted really smoothly. Then after about 15 mins driving around town again it started to slip. I then proceeded to go onto the highway... drove for another 2 hrs.. (no slips between 3rd and 4th) and got to my final destination. When i arrived at first there were no slips. Then after around that 15 min mark it started to slip again until i got home. When i got home i checked the slave and did not see any fluid leaking out and my reservoir and it was still at max. Does this still seem like the actual clutch, alignment, master? (if this has any effect on the answer in the previous posts).

Thanks!

Stretch · #26 10-14-2015, 06:21 AM

I'm of the opinion you need to start making some in-depth investigations. Either / and / or

1) try and measure the clutch wear with the home made tool as per the instructions in the FSM
2) remove the slave cylinder and see if it operates correctly and then bleed the clutch
3) remove the gearbox and have a look at the condition of the clutch plates

The choice is yours!

There are of course other options such as living with it as it is but I guess it will eventually get worse and if it is a little thing like the slave cylinder it will eventually cost you more money to replace the clutch.

Frank Reiner · #27 10-14-2015, 11:30 AM

Quote:

Originally Posted by Stretch

I'm of the opinion you need to start making some in-depth investigations. Either / and / or

1) try and measure the clutch wear with the home made tool as per the instructions in the FSM
2) remove the slave cylinder and see if it operates correctly and then bleed the clutch
3) remove the gearbox and have a look at the condition of the clutch plates

Stretch:

Consider also that the clutch master cylinder push rod could be adjusted too tight; the piston will be held in a position in which it covers the fluid entry/release port. In that position system pressure never drops to zero, and as the fluid temperature rises, pressure increases. If pressure rises enough, the clutch could be held in a partially released condition, i.e., slipping.

Stretch · #28 10-14-2015, 11:53 AM

Quote:

Originally Posted by Frank Reiner

Stretch:

Consider also that the clutch master cylinder push rod could be adjusted too tight; the piston will be held in a position in which it covers the fluid entry/release port. In that position system pressure never drops to zero, and as the fluid temperature rises, pressure increases. If pressure rises enough, the clutch could be held in a partially released condition, i.e., slipping.

I completely agree - I tried to say as much earlier in the thread but I don't think I said it quite so clearly.

The point I'd really like to get across though is there's no point driving and dreaming - some sort of investigation needs to be done!

ollo · #29 10-15-2015, 11:12 AM

"The point I'd really like to get across though is there's no point driving and dreaming - some sort of investigation needs to be done!"

Dredging up memories from 50-60 years ago, when nearly all cars we drove had manual transmissions, most of us learned this lesson.

You could drive keep driving the car for a while with a failing(fill in the blank) transmission, clutch disk, pressure plate, release bearing, pilot bearing or hydraulics. Sooner or later(usually sooner) a repair was needed, then you could get on with life. Don

mannys9130 · #30 10-15-2015, 12:32 PM

If it's not slipping at all in 4th on the highway, I'm inclined to think something is hanging up. When a clutch starts to go, it'll slip in top gear first then make its way down.