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Discussion Starter · #1 · (Edited)
Hi my name is Joel and I’m a Bronco addict. Lol.
Ive got an 88 Bronco which I just bought for $700. Currently I’m replacing the front wheel bearings. My horse came with flanged manual hubs. In cleaning everything up to install the new bearings and seals I noticed that my seals sit really loose in the back of the rotor. They measure 3.50” in diameter (National Seal #710091). The race where the seal goes measures 3.70”. The race shows absolutely no signs of wear. The brakes were new as well when I began to tear them down. I’ve looked everywhere to find out how to ID these rotors. Bronco had a break in engineering in May of 1988. My mfg date on the VIN tag says 9/87. I think I have a “mut” horse. Lol. Can anyone offer data that will help me ID the spindles and rotors? This is all info for the passenger side so far. I haven’t torn down the driver side yet but it had little play. The PS had about 1/8” - 1/4” play in the wheel when I tore it down. I expected to see shredded bearings and metal shavings everywhere. After cleaning all the parts... every part looks new and no signs of wear. Yeah I hate it when that happens too. Lol. Anyways.... any advice would be greatly appreciated.
Btw.... thanks for all the great topics and advice. These forums have really helped me take my horse from a corn field abandoned Bronco to a great fun project and stress reliever. Thanks again!

Addicted to Junk
85 Bronco, 309ci I6 w/4bbl, np435, 4" lift, 37" Irok NDs, 4.56 w/ Detroit Locker and tru trac
16,367 Posts
I cant really help as I have no experience with those rotors. Those came on 87s and half of the 88s. They are called Top Hat Hubs by most people.
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Super Moderator
29,131 Posts
Yo Joel,
I'll move this thread to Noobie section for better visibility.

87-88 spindle on the left. Upgraded 90' spindle on the right.
by Eric D (Beast, B-Man)
Eric trashed the flange hubs, etc to go to a 90 design @ 1988 Ford Bronco Knuckle out conversion manual locking hubs pictures, videos, and sounds |

Dana 44 Knuckle Differences through the Years; "...80-85 Knuckles have bolt on calipers and 6 bolts holding the spindle to knuckle. I consider these strongest. 1993 Knuckles have tension pin style calipers and 5 bolts holding the spindle to knuckle. 87-92 Knuckles have tension pin style calipers and 6 bolts holding the spindle to knuckle. 94-96 Knuckles have two bolt style calipers and 6 bolts holding the spindle to knuckle. Also have ABS provision..."
Type 1: 80-93 but NOT 1987
Type 2: 1987...
Type 3: 94-96"&
"80-92 Spindles are six bolt and the same except for 87 with "top hat"...
Source: by philofab


"80-92 Spindles are six bolt and the same except for 87 with "top hat" by Steve

Will post more info when my internet speeds up to at least 1992 levels.

Here's the 1988 Ford Bronco & Truck Service Manuals by Larry J via Kingfish999 in Google Drive @ 1988 Ford Truck Service Manuals (Thank you Larry Jorgensen) - Google Drive

1988 Bronco Dealer Brochure @

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via BroncMom

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Premium Member
93 XLT 347, GT40 Heads, Bassani headers/exhaust, E4OD
1,767 Posts
The information from @BigBlue 94 and @miesk5 has you covered (and I have no direct experience with the top hat spindles either), but this may help...

The TTB front ends were built by Dana/Spicer for Ford. What parts you need aren't so much dictated by the year of your Bronco, but the "Bill of Materials" or BOM number Dana used to identify the front end assembly used on your truck. Not sure where you'll find it on an '88 (tag on front differential bolt, stamped to the right of the differential on the drivers side axle, or a label in the rear of the passenger side axle - it apparently varied over the years and say on my '93 it's a label on the passenger side).

Once armed with the BOM number, this catalog becomes a treasure trove of information and will identify the exact Dana part number for the seal you need.

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