Keep breaking center pins
Thread Starter
|
Mountain Pass
Joined: Jun 2002
Posts: 185
Likes: 1
From: St. Petersburg, FL
Keep breaking center pins
OK, this will be the 3rd time I've replaced the pins, last time was about 2 1/2 months ago. The pins that keep the axle centered on the leak springs, anyone have an idea why I keep breaking them? I don't haul any really heavy loads, and I only trailer a small flats boat or a utility trailer. .....I'm getting fed up.
thanks for any help
thanks for any help
Postmaster
Joined: Jan 2005
Posts: 2,753
Likes: 3
From: Phenix City, AL
Only thing I can think of is too much axle wrap. Either that or cheap pins, make sure they are grade 8 or better.
How big are the blocks you are using?
Are all your spring keepers in place and are all the u-bolts torqued properly?
I'm fishing here, would be easier with some pics.
How big are the blocks you are using?
Are all your spring keepers in place and are all the u-bolts torqued properly?
I'm fishing here, would be easier with some pics.
Thread Starter
|
Mountain Pass
Joined: Jun 2002
Posts: 185
Likes: 1
From: St. Petersburg, FL
the last time I replaced the bolts, I went up to Home Depot and got some hardened steel bolts. Maybe that's the problem.
As far as blocks go, I've got 2 of the stock F-250 blocks stacked on each side, so it's a total of about 3.5-4"
Spring keepers are all OK, and the U-bolts are torqued down.
As far as blocks go, I've got 2 of the stock F-250 blocks stacked on each side, so it's a total of about 3.5-4"
Spring keepers are all OK, and the U-bolts are torqued down.
Postmaster
Joined: Jan 2005
Posts: 2,753
Likes: 3
From: Phenix City, AL
They may be hardened, but make sure they are grade 8 at least. Grade 5's will come apart on you.
The stacked blocks don't help either. I've never been a real big fan of that.
I would start with the bolts and if you can, get some single 350 blocks. They are 4". The SD's are prone to axle wrap with lift. It can be a pain.
The stacked blocks don't help either. I've never been a real big fan of that.
I would start with the bolts and if you can, get some single 350 blocks. They are 4". The SD's are prone to axle wrap with lift. It can be a pain.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 422
From: Long Island USA
That's very strange...
If the u-bolts are torqued down correctly, the friction between the leaf and the axle will keep it from moving anywhere. Those pins are really just for locating the axle before you get the u-bolts tightened, they shouldn't see any load under normal conditions.
Did you use NEW u-bolts or re-use the old ones?
Since the F350's used 4" blocks, I don't think that's the problem, although stacking two 2" blocks doesn't help the u-bolt tension.
The only other thing I can think of is, did you put other leafs in the spring pack that have more arc than the rest?
If the u-bolts are torqued down correctly, the friction between the leaf and the axle will keep it from moving anywhere. Those pins are really just for locating the axle before you get the u-bolts tightened, they shouldn't see any load under normal conditions.
Did you use NEW u-bolts or re-use the old ones?
Since the F350's used 4" blocks, I don't think that's the problem, although stacking two 2" blocks doesn't help the u-bolt tension.
The only other thing I can think of is, did you put other leafs in the spring pack that have more arc than the rest?
Thread Starter
|
Mountain Pass
Joined: Jun 2002
Posts: 185
Likes: 1
From: St. Petersburg, FL
thanks for the help guys. I'm starting to think the bolts I used might be the problem. I have no idea if they were grade 8, so they probably were not. The blocks used to be welded together, but have since come apart. I'll try to come up with some F-350 blocks to stick in there. The U-bolts were new with the lift (45k miles ago), but they're still in good shape.
it's gotta be the bolts/pins.
it's gotta be the bolts/pins.
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 422
From: Long Island USA
Originally Posted by Big Red F250 SD
The blocks used to be welded together, but have since come apart.
I would seriously look at the u-bolts, and make sure they are thick enough (and strong enough) to keep everything together.
Something doesn't sound right.
By the way, I used a grade 3 piece of threaded rod once, for the leaf spring pin, on my '74 highboy, never broke it, and that thing went four wheeling though lots of hard stuff. There shouldn't be so much flex there that the bolt would break.
Seriously, those U-bolts are VERY suspect...
Maybe the spring perch is not perfectly flat... that wouldn't help, especially if it's been flexing enough to break the pin and the welds on those blocks.
Or, you're beating the heck out of it
Trending Topics
Thread Starter
|
Mountain Pass
Joined: Jun 2002
Posts: 185
Likes: 1
From: St. Petersburg, FL
update: The problem was a loose nut on a U-bolt on each side, that allowed axle flex ~~ broken center pins. I really had them torqued down w/ an impact wrench too. This time, I took a torque wrench to them after the impact wrench, so hopefully they'll stay tight. thanks for your help again
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Butt-Head
Joined: Apr 2004
Posts: 9,429
Likes: 2,915
From: Reed Point, MT
Originally Posted by Big Red F250 SD
update: The problem was a loose nut on a U-bolt on each side, that allowed axle flex ~~ broken center pins. I really had them torqued down w/ an impact wrench too. This time, I took a torque wrench to them after the impact wrench, so hopefully they'll stay tight. thanks for your help again
Use new u-bolts, new nuts, and 120-130 ft.lbs. TOPS.
Cody
Lead Driver
Joined: May 2003
Posts: 9,303
Likes: 48
From: Lyndonville, Vermont
Krewat is right on. Those bolts don't do much after the u bolts are tight .
Grade 8 is not neccessary. There's little stress on the bolts. The u bolts do all the work . Make sure the ubolts are tightened evenly or you will find one loose also check them after you have driven the truck for awhile. Don't use welded blocks and no higher than the f350 units. The only way the bolts will break is to have really loose u bolts.
Dick
Grade 8 is not neccessary. There's little stress on the bolts. The u bolts do all the work . Make sure the ubolts are tightened evenly or you will find one loose also check them after you have driven the truck for awhile. Don't use welded blocks and no higher than the f350 units. The only way the bolts will break is to have really loose u bolts.
Dick
Thread
Thread Starter
Forum
Replies
Last Post