Cummins A/C bracket retrofit.

[The Gibster]

ISB Cummins in FL70s are well known for their vibration problems, one direct problem associated with them is that the A/C Compressor mounting ears break off at the mounting bracket. Poor bracket design!

We've heard that Freightliner in DFW has been able to fabricate another bracket that goes over the top of the compressor and solves the vibration and linear torque problem.

Has anybody had first hand knowledge of the bracketry retrofit, or know of a shop that does the fabrication?


The Gibster

 

[davekc]

We had a old FL70 that went through 3 or 4 of those.
I thought they had a permanant replacement for those?
Maybe not.
What does FL or cummins say?

Davekc

 

[The Gibster]

Cummins only handles the engine itself, and state that the compressor and associated bracketry is a freightliner part/issue.

In 2 years Dave this is our 5th A/C compressor. Donna is absolutely great for saving all our receipts, and freightliner replaces each one under warranty. But it does mean 2-3 days downtime (as usual) at freightliner.

When we were at Cummins the other day in Joplin MO the tech took out his ball point and drew out on top of my front tire what a bracket should look like - apparently Detroit Diesel had a similar problem with Bendix alternators and brackets. Wiggled the snot right out of them. Detroit blamed Bendix; Bendix said oh no, the brackets are the fault. The techs got tired of the problem and started manufacturing their own brackets.

Granted it's a warranty repair, and Freightliner keeps replacing them. And we've always caught the broken compressors before they sling off into the front of the engine. But it only takes once . . .

And we had the new engine installed by Pete because I would just as soon never set foot in a Freightliner dealership again if I didn't have to.

I am even willing to foot the $250 I have heard the retrofit cost the O/O. I'm trying to find who can do it so we know which way to point the nose to go get the thing fixed once and for all.

Do you know of anyone doing the retrofit Dave? Any suggestions, machine shops, etc?


The Gibster

 

[RichM]

I have an ancient FL 70 with the Cummins C series. I was told by by a FL mechanic way back when to never turn on the A/C when you are moving. Wait till you are in a idle state and turn it on . I have followed that advice and have never had a problem.Apaarently the clutch can cyle on/off ok when you are moving but turning it on from a
off state beats it up.

 

[davekc]

I thought I read somewhere that there is a retro fit.
For the sake of speed, I can think of two items.

The first is to have the part on hand so it doesn't have to be ordered. This will eliminate some downtime.
Forget freightliner and go to a Western Star or Sterling only dealer.
This will cut some more of the wait time down, and still get the work done under warranty.

If a retro fit doesn't exist, a welding/metal shop may be able to heat and braze an existing one. This has to be done correctly because as it is heated, you don't want to weaken the existing metal.
This is better done with an arc welder.

The other issue is to call Freightliner for service bulletins relevant to your problem. That will answer whether they are using the right part. From experience....don't assume they are.

Example; we had our A/C repaired 3 times at Houston Freightliner.
This is on a fl70. Broke again and repaired correctly at Dothan Freightliner. The problem was they were using a old part that was deemed defective by freightliner. The service clearly identified the difference in parts and the wrong one was used.
Repair was free with minumal downtime, but the days it is costing you can't be recovered.

We had that same part changed out and the last one didn't give us any trouble. I thought it was a little different than the original.
I also remember that Lock-tite was used on the bolts to secure it.

Bear with me, as I am trying to remember back about 8 or 9 years.

Hope that helps
If you run into more issues with it,
Give me a call.

Davekc