Rear Axle U Bolt Retorquing

D

Deleted member 50714

Guest
Re: Membership is declining.

I spent days pouring over volumes of MB publications and can't find any info on the practice of ringing and pinging?:idunno:
 

lindenengineering

Well-known member
Re: Membership is declining.

I spent days pouring over volumes of MB publications and can't find any info on the practice of ringing and pinging?:idunno:
No you probably won't.
The usual stock answer you will get from German companies AND individuals alike --Why are you questioning this --you should know these things if you are working in this industry.
Dennis
 
D

Deleted member 50714

Guest
Re: Membership is declining.

No you probably won't.
The usual stock answer you will get from German companies AND individuals alike --Why are you questioning this --you should know these things if you are working in this industry.
Dennis
I spent days pouring over volumes of MB publications and can't find any info on the practice of ringing and pinging?:idunno:
I forgot to put this :dripsarcasm:
 
D

Deleted member 50714

Guest
Re: Membership is declining.

Here is the geniune MB service pub.

Just re-torque them as it sits. I have done both way's and the results were the same. I can find the toque spec for you tomorrow. I have it wrote down in tool box.
I agree, not that you or others require my agreement. I'm thinking raising the vehicle is only a convenience for the mech/tech. Torquing with the Vehicle NOT raised shouldn't have any adverse effect on the torquing procedure?
 

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mitchcraft

Learning to wrench on 05
Re: Membership is declining.

If there is a tendency for these nuts to loosen,why not use a locknut that does not back off?
 
D

Deleted member 50714

Guest
Re: Membership is declining.

It's not so much the nut backing off. Steel has a certain amount of elasticity and requires re-torquing to compensate for stretching. Torquing is stretching the bolt to specified limits.
 
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mitchcraft

Learning to wrench on 05
Re: Membership is declining.

What about higher grade of bolt?In 45yrs of wrenching on pickups never had to do this procedure.
 
D

Deleted member 50714

Guest
Re: Membership is declining.

What about higher grade of bolt?In 45yrs of wrenching on pickups never had to do this procedure.
Excellent question and same here, had an affinity for 67 Cheby's [sic] pickups, 350 and turbo 400 roarrrr! I can't answer the question because I don't know. WAG is it should have been done? Maybe German steel is wimpier than AMERICAN steel? Yeah, that's got to be it. :smirk:
 

mikeme

2015 LTV IB: 2015 3500 V6
Re: Membership is declining.

What about higher grade of bolt?In 45yrs of wrenching on pickups never had to do this procedure.
There is no free lunch.

MB could revise the design to eliminate the need for this re-torque.

but it would not be substitution of a higher grade "bolt"


a common misunderstanding is that higher grade bolts are "better"

they are different.

increased hardness comes with increased brittleness. which means for this application, that they would be faster to crack in half, instead of stretch a bit.

ask me which I would rather have, a maintenance item, or suspension fasteners which fall off.

it could well be that the new design we see in a couple years will not need this activity.

and thanks to Dennis for bringing this up.

(we are picking up an 18,000 mile 2015 3500 chassis with an LTV unity bolted to it next week.....torqueing these bolts will be on the list for the first couple days.)
 
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avanti

2022 Ford Transit 3500
Re: Membership is declining.

So, I have a question:

The Mercedes maintenance regimen specifies a one-time re-torque of theses bolds at the first "A" service. This implies initial stretching that then stabilizes. Is this the case? That is, is the procedure that Dennis is reminding us about a one-time thing, or is the Mercedes guideline inadequate with the bolts needing to be checked on a regular basis?
 

mikeme

2015 LTV IB: 2015 3500 V6
Re: Membership is declining.

I would guess that we do not have the background analysis behind this.

it could well be that the adjustment is for deformation of the top of the U bolt around the spring, not stretch in the bolt itself.

if so, this would be consistent with a single adjustment after some use.

I do like the ping check.
 
D

Deleted member 50714

Guest
Re: Membership is declining.

When I retorqued the shackles (U-Bolts), for future reference, I marked the torque order and value.
 

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showkey

Well-known member
Re: Membership is declining.

^^^^^^^you really need to get out more:cheers:

Maybe a new hobby:thumbup::dripsarcasm:


That undercarriage really needs to washed, detailed and polished.............
 
D

Deleted member 50714

Guest
Re: Membership is declining.

^^^^^^^you really need to get out more:cheers:

Maybe a new hobby:thumbup::dripsarcasm:


That undercarriage really needs to washed, detailed and polished.............

You're right, I didn't notice how filthy! I plan to detail the undercarriage tomorrow. By the time I plan on re-torquing the "shackles," sounds kinky, I'll have forgotten the torque order/value and where I put it in my notes. It's a minor task, taking less time than looking for the specs. Good exercise crawling around.
 
Re: Membership is declining.

I checked the nuts on the axle of our 2013 - 3500 camper van. I had to pull the wrench a few times on each nut to get them up to the
125 ft.lbs specified. The van was at the dealer less than a month ago for a B service. I'm not sure if they checked the nuts. The van only had about 16000 kms. on the clock but it has been on the road for 3 years.
 

sailquik

Well-known member
Re: Membership is declining.

TOASTER.13
It's a one time only (first "A" service @ 10k (16k km) to 20k (32k km) miles depending on
the service schedule for your Sprinter's model year (MY)) item in your Sprinter's Maintenance
Handbook.
I suspect it's often overlooked, particularly on RV (where it may be far more important).
Note a bad idea to recheck them from time to time, but once the U-bolts initially "stretch
they are supposed to retain that torque over time.
With the number of loose U-Bolts or missing spring locator pins on this forum it would seem
that this is a good thing for all Sprinter owners to check themselves, or ask to have checked
during regular maintenance at your authorized MB Sprinter dealer or independent shop.
Roger
set
 

MeRob

Member
Re: Membership is declining.

It would now appear that having no choice but to drive over the bumps of a particularly rough stretch of a Detour Road? ... has caused my RV rear spring U-Bolts to loosen up. This would explain my driving comfort instantly changing from acceptable... to that of an upholstered brick! NO 'PING' on U-Bolts ...not even a good thud!

Does anyone know what the Torque Setting should be on the 3500 rear U-Bolts? ....

...and Thanks for the 'Ping" advice! .... Rob
 
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