My son and I were removing his summer wheels to install the snow tires and one of the wheel bolts broke off in the hub. I went to a friends garage and managed to drill the broken bit out to 3/8 inch. Then I figured I could run a tap through to remove the remainder of the bolt material still stuck in the threads of the hub. No bueno....the tap will not thread the hole. I assume the bolt material is harder than the hub, but I'm out of ideas what to try next. Local garage quoted him $1000 to repair it, dealer was $1250, so I'm open to lesser cost ideas.
Trent
PowerDork
11/29/21 4:45 p.m.
What fiat?
I assume a modern 500? Front or rear hub? I know they are M12X1.50 lug bolts. The tap drill for that size is 0.414" or 10.5mm. 13/32" would do in a pinch. But there is no way a tap will start in the .375" hole
Would it be cheaper/quicker just to put a new hub on as opposed to drilling it out?
-Rob
In reply to Trent :
Current Fiat 500, front hub, my thread gauge says they're M12x 1.25 (my MINI is M12x1.5 so I can see the difference), and my tap nose went in until it was flush with the back of the hub, but I'll go get a bigger drill in the morning. Thanks Trent.
In reply to rob_lewis :
The hub is one of those pressed in with the bearing designs, so I would need hub, bearing and a press. If this were my Miata I'd have a new hub in an instant.
DeadSkunk (Warren) said:
In reply to rob_lewis :
The hub is one of those pressed in with the bearing designs, so I would need hub, bearing and a press. If this were my Miata I'd have a new hub in an instant.
Shoot, figured you'd thought about that, but sometimes it's hard to see the forest for the trees, so I thought I'd offer the option.
-Rob
Trent
PowerDork
11/29/21 8:37 p.m.
DeadSkunk (Warren) said:
In reply to Trent :
Current Fiat 500, front hub, my thread gauge says they're M12x 1.25 (my MINI is M12x1.5 so I can see the difference), and my tap nose went in until it was flush with the back of the hub, but I'll go get a bigger drill in the morning. Thanks Trent.
For M12X1.25 the tap drill size is 27/64" or 10.75mm.
In reply to Trent :
Local Menards shows that in stock, so first thing in the morning I'll get one. Thanks again.
Follow up: Thanks Trent for the info. This morning I ran the 27/64ths drill through the hub and all the old thread material from the bolt basically fell out. Ran the tap through it to clean it out and everything is golden now. Lug nut is in, anti-seize on it and torqued to spec, and it saved my son from a $600 bill for a replacement hub.
Edit: My original post said $1000-$1250, but a second Chrysler dealer service manager quoted $594 and figures the other places were likely quoting replacing both sides. He was also much politer to my son and has now gained a new customer for any service the Fiat may need in the future.
Trent
PowerDork
12/1/21 11:30 a.m.
Excellent news! Glad I could help
