Bent chassis
Submitted: Sunday, Sep 06, 2009 at 07:42
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Member - DW (NSW)
Hi all
I have a slightly bent chassis on a Mazda Bravo, about half way between the axle and the rear spring hanger on both sides.
The springs appear to have lost their camber as the hangers are sloping back as if heavily loaded even with nothing on the back.
I am almost sure
the springs have caused the problem. The vehicle tows a
Kimberley Karavan which is not the lightest on ball weight but is a
well balanced trailer.
Several replies I have had indicate that heavier springs are needed. These springs are not the original Mazda springs. They give the impression of Toyota springs that have sagged. I also have Firestone airbags fitted but have not over inflated them to compensate.
My son has had 3 Bravos that have usually been overloaded and tow overloaded bogey trailers as
well. He has had no problems at all. Now his company is going to either Mazda BT50 or Ford
Ranger for the same work.
Any suggestions on repairs would be welcome.
Cheers
DW
Reply By: Member - Phil G (SA) - Sunday, Sep 06, 2009 at 09:06
Sunday, Sep 06, 2009 at 09:06
DW,
Sorry to hear of the nasty problem.
I've seen it a fair bit on dual cab utes (Hilux, Rodeo and Navara)and its caused by a combination of factors:
- Too much weight behind the rear axle
- Towing - that ball weight is a long way behind the axle
- Polyairs and heavy springs
- Offroading - particularly bouncy
sand dunes and hitting holes etc
So the heavy springs and polyairs act as a fulcrum, and the weight behind the axle cause the chassis to bend. As it bends, the tailshaft shortens and puts heaps of pressure onto the diff.
How to fix it? Its not going to be cheap. Consider firstly whether it might be a legitimate insurance claim - maybe you've hit a wombat hole in your travels??? If it is, then its the insurance company's problem. If not, then you'll need to get it assessed by a company that specialises in chassis work. In
Adelaide people go to ChassisTech. Don't know where you'd go in NSW.
Best of luck with it.
Can I suggest you change to a vehicle with 3500kg towing capacity that has a good strong chassis (eg LandCruiser).
AnswerID:
382132
Reply By: DCTriton - Sunday, Sep 06, 2009 at 11:27
Sunday, Sep 06, 2009 at 11:27
Nearly every incidence of chassis bends in the area mentioned, that I have come across, has involved after market airbag set ups - those that didn't involved stupidly overloaded or seriously airborne vehicles...
AnswerID:
382149
Follow Up By: Dust-Devil - Sunday, Sep 06, 2009 at 14:42
Sunday, Sep 06, 2009 at 14:42
Seriously Airbourne ?????????
How does one define that term
FollowupID:
649712
Follow Up By: Member - Tony & Julie (FNQ) - Sunday, Sep 06, 2009 at 15:52
Sunday, Sep 06, 2009 at 15:52
4
wheels off the ground as one does when jumping
sand dunes , good way to bend diffs and chassis. Cheers Tony
FollowupID:
649717
Reply By: Member - Tour Boy ( Bundy QLD) - Sunday, Sep 06, 2009 at 15:11
Sunday, Sep 06, 2009 at 15:11
Our old builder had that happen on his rodeo a couple of years ago, he just kept putting spacers under the rear of the tray to make it look level until it had 1 inch more in the rear than the front...then he traded it...dealers problem then.
Pretty common with most makes of dual cabs these days I'm afraid.
Cheers
Dave
AnswerID:
382161
Reply By: travelguy62 - Sunday, Sep 06, 2009 at 18:54
Sunday, Sep 06, 2009 at 18:54
DW,
Any good panel
shop with a rack should be able to straighten the chassis and fit fish plates to strenghten the rails to stop this problem.
Cheers Guy
AnswerID:
382177
Reply By: Member - DW (NSW) - Monday, Sep 07, 2009 at 05:47
Monday, Sep 07, 2009 at 05:47
Thank you all for your thoughts. I can assure you that is has never been airborne. However, the airbags may have been part of the problem along with weak springs and towing.
Today, I am visiting my 4wd service
shop for them to have a look at it, as I have just returned from the Red Centre on last Friday.
Hopefully, the issue can be resolved successfully otherwise it may be the spacer trick and see it later.
Cheers
DW
AnswerID:
382222