[adben11]

Hello, I have noticed a leak from the Transmission Pan on my 91 420. When I crawled under it, the bolts for the pan were pretty loose. I was able to get at least a full turn out of all of them. But with a 14mm socket on a 1/2" drive wrench, I was pretty nervous about stripping out or breaking off the bolts.
Does any one know what the proper torque for these bolts is? I would feel a whole lot better if I knew this and could use the proper wrench to make sure that I am getting them to the proper tightness.
I am also thinking of pulling each one and putting some blue locktite on them
TIA

 

[nobby]

Hello, I have noticed a leak from the Transmission Pan on my 91 420. When I crawled under it, the bolts for the pan were pretty loose. I was able to get at least a full turn out of all of them. But with a 14mm socket on a 1/2" drive wrench, I was pretty nervous about stripping out or breaking off the bolts.
Does any one know what the proper torque for these bolts is? I would feel a whole lot better if I knew this and could use the proper wrench to make sure that I am getting them to the proper tightness.
I am also thinking of pulling each one and putting some blue locktite on them
TIA

Quick search found it to be: torque to 8 Nm.

FROM: Do It Yourself (DIY) repair thread and wheel and tyre thread | Mercedes-Benz Forum (benzworld.org)

(6 ft. lb or 71 in. lb.)

 

[isthenew]

Ohhhhh man, if you used a 1/2" drive, you're gonna be waaaaaaay past spec. Says the guy that never did anything to spec until I learned that over tightening the transmission pan leads to worse leaks.

You should really redo this to spec. And be sure to use the proper pattern: same as for a head gasket, not a cross-pattern.

 

[nobby]

Ohhhhh man, if you used a 1/2" drive, you're gonna be waaaaaaay past spec. Says the guy that never did anything to spec until I learned that over tightening the transmission pan leads to worse leaks.

That would be 1/2 grunt with 3/8 drive.

Honestly I really only use a torque wrench on wheels, spark plugs and heads. Everything else is mechanic feel.

 

[rumb]

Now that you have crushed the gasket you will need a new one.....

 

[dedgar]

That would be 1/2 grunt with 3/8 drive.

Honestly I really only use a torque wrench on wheels, spark plugs and heads. Everything else is mechanic feel.

So you can mechanic feel 6 ft-lb? That's what 8 nm is. Tighter than that is crushing the gasket.
Tighten all the bolts to 4 nm. Then tighten them an additional 90 degrees (after they all were taken to 4nm). That comes real close to 8 nm.

 

[rumb]

Nobby is super human!

I bet he can also feel .01mm play in wheel bearings.

The rest of us mortals have to rely on tools....

 

[MBL87560SEC]

Nobby is super human!

I bet he can also feel .01mm play in wheel bearings.

The rest of us mortals have to rely on tools....

“That would be 1/2 grunt with 3/8 drive.

Honestly I really only use a torque wrench on wheels, spark plugs and heads.
Everything else is mechanic feel.”

I’m with Nobby here.

All those years working as a mechanic/technician, one gets a feel for tightening fittings, fasteners etc.
Call it muscle memory if you will.

I know exactly what he refers to.

M

 

[Gumpy]

Let's see - 6 pound-feet. Back in the day I would agree on 1/2 grunt or less, but as one gets older it is now somewhere between a "little squeak" and "two dribbles".

 

[John350]

Actually, it has nothing to do with numbers. An experienced mechanic can feel when a fastener is getting tight. It varies depending on whether it's a metal to metal joint or a soft rubber gasket, but you still develop a feel for it.

 

[nobby]

 

[isthenew]

View attachment 2813135

I'ma steal this cuz it's totally my patients

 

[adben11]

Ok Thanks. I am going to replace the gasket (if I can find one) I am hoping that there is only one for that year since I don't think I would know the difference in them. I know that it is a 6 bolt pan, But I don't know the tightening pattern, trying to find that now and also the total amount of fluid I will need. Think I can find that in my owners manual.
Thank

Just noticed the link Nobby had in the very first reply, Thank you!

 

[John350]

But I don't know the tightening pattern,

This pattern can be adapted to just about anything you'll come across, from cylinder heads to timing covers to oil pans. (Easy to remember, too!)

 

[adben11]

Thank you!

 

[260e crusier]

When I crawled under it, the bolts for the pan were pretty loose. I was able to get at least a full turn out of all of them. But with a 14mm socket on a 1/2" drive wrench, I was pretty nervous about stripping out or breaking off the bolts.

14mm bolt on the pan?