Bronco Forum - Full Size Ford Bronco Forum banner

1 - 19 of 19 Posts

·
Registered
Joined
·
51 Posts
Discussion Starter #1
I'm starting to look for an '80-96 full-size Bronco for my next project (wrapping up the GF's '49 Jeep Willy's right now) and would like some input from those of you in the know on the FSB's.

This will be my first Bronco so I have no personal knowledge of the in's and out's of these things. . .

. . .do the frames have any weak points that deserve special attention?

This won't be a race vehicle (at least that's not the initial intention), but will be street legal pre-runner that will see off-road use. I'm planning on doing a 4-link rear and all new TTB in front with coilovers and bypasses. . .

. . .if more info is needed to answer the question just let me know.

Thanks!!!
 

·
Registered
Joined
·
52 Posts
Frames don't have weak points per se. The frames were designed to flex. Stay away from the early trucks as they had large holes in teh frame. Plan on replacing the rivets with grd 8 hardware. Some folks prefer to bolt accessories (cage and such) others weld. They both hold up. The only part that I have ever seen crack on teh frame is teh cross member and that is from the lift kit brackets. Plan on going with cut and turned beams for strength. Look forward to you build. I have seen many of your posts on race dez and you bring up some interesting questions and points.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #3
Thanks Damon1272!!!

I'm pretty disappointed to hear about the rivets in the frame though. . .you have no idea how much time, grinding wheels, or how many punches I went through hammering all the rivets out my GF's '49 Jeep Willy's frame!!!. . .not to mention the sore muscles and arms that I couldn't even lift over my head at the end of the day after going to town on countless number of rivets with a small sledge!!!

So the FSB frames are pretty solid. . .besides the crossmember would you suggest bracing/reinforcing the frame anywhere?

I'm gonna be doing this build from the ground up. . .I did the '49 from the ground up and I learned a LOT from that experience. . .there are a lot of things I would have done different if it was just my truck, but it's here truck and time frame was more important than changing things to make them better. . .

. . .glad to hear from another RDC member on this forum. . .I'm a big fan of the FSB's, but I've never been in the position to get a "project vehicle" that was just that, a project vehicle, and not something I had to depend on for one reason or another while I was in the middle of building it, but I should be getting a nice windfall soon and I should be able to afford an FSB and some nice parts to get a good start on it.

I'll be running a build thread on here and RDC when I get one. . .contingent on the windfall anyway.
 

·
Super Moderator
Joined
·
25,853 Posts
yo,
I have a bunch of Frame Info/resto LINKs in my site @ http://www.broncolinks.com/index.php?index=37


for example here are some;
Frame Strength & Dimensions in 80-96; "...This got me thinking and I just found my Standard Catalog of 4x4s book. It has info on every model year domestic 4x4. It doesn't really specifically talk about frame differences from year to year, but it does have a Chassis Features section for each Bronco year. Here's what it has: (1980-1985) Separate body and frame, box-section welded frame. 3.95 in. section modulus (1986) Separate body and frame, single channel, 5 cross members, welded frame. 3.66 in. section modulus. Maximum side rail section: 6.95 x 2.12 x 0.170 in. (1987-1989) Separate body and frame, single channel, 5 cross members, welded frame, 36,000 psi steel. 4.27 in. section modulus. Maximum side rail section: 7.01 x 2.12 x 0.202 in. (1990-1992) same as 87-89 but also notes low carbon steel (1993-1996) Separate body and frame, single channel, 5 cross members, welded frame, 3.66 in. section modulus. Maximum side rail section: 6.95 x 2.12 x 0.170 in. low carbon steel..."
Source: by BurntOrange at http://www.fullsizebronco.com/forum/showthread.php?t=10525
===
Frame Strength, Bronco, F-Series, F-Super Duty Chassis Cab all use a 36,000 psi steel frame.
Source: by Ford via Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/clubs/superford/registry/media/194329
"...Frame Service - Drilling Precautions

CAUTION: Do not drill holes in the frame flanges. This will reduce the strength of frame (5005).

If a hole must be drilled in the frame, make sure that it meets all of the following requirements:
1. The hole is located in the upper half of the frame.
2. The edge of the drilled hole and the edge of the nearest hole are at least 25mm (1 inch) apart.
3. The edge of the drilled hole is at least 25mm (1 inch) from the edge of the flange.
4. The drilled hole is not adjacent to any other existing brackets or components of frame.

Welding Precautions

CAUTION: Disconnect the battery ground cable (14301) before using any electric welding equipment.

All welding on frame must be done with electric welding equipment, and the heat should be kept in a small area to prevent change in hardness of the metal. Do not use gas welding equipment. A double reinforcement must be added to frames where heat or weld is applied to the area to be repaired. The welds are to run lengthwise along the reinforcement when a reinforcement is to be welded to the frame side rail.

Frame Strength Identification
F-Series, F-Super Duty Chassis Cab and Bronco all use a 36,000 psi steel frame.

Frame Straightening
Misalignment of frame can be corrected by straightening the out-of-line parts or by replacing the crossmembers, braces, or brackets if they are badly damaged.

WARNING: DO NOT STRAIGHTEN FRONT FRAME RAIL CONVOLUTES.
Straightening should be attempted on frames that fail to meet specifications of the diagonal checking method or where damage is visually apparent.

However, to prevent internal stresses in the metal, frame straightening should be limited to parts that are not severely bent. If heat is needed to straighten a frame member, keep the temperature below 649�C (1200�F) (a dull red glow). Excessive heat may weaken the metal in the frame members and cause permanent damage.

Frame Reinforcing

After a bent frame member has been straightened, inspect the member closely for cracks. If any cracks show, the frame member should be reinforced or replaced.

Reinforcements should be made from angle or flat stock of the same material and thickness as the frame member being reinforced, and should extend a minimum of 152.40mm (6 inches) to either side of the crack. Ideally, the reinforcement should be cut from the corresponding area of a similar frame.

Weld Attachment

To ensure a quality repair, adhere to the following procedure if it is necessary to weld reinforcements to the frame.
1. Wire brush the area around the crack to remove the paint, grease, mud, etc., and to expose the crack completely and ensure good weld adhesion.
2. To stop the crack from spreading, drill a 6.35mm (1/4-inch) hole at a point 12mm (0.50 inch) beyond the root of the crack.
3. Grind out the full length of the crack to the hole to form a V-shaped slot with the base of the V-slot contacting the reinforcement.
4. The base of the V-slot should have at least a 1.52mm (0.06-inch) opening to ensure weld penetration to the reinforcement when welding the crack.
5. Drill clearance holes in the reinforcements to clear rivet heads and bolt heads or nuts where necessary.
6. In the event that repair is required on more than one frame surface (i.e., a flange crack that extends into the web), two pieces of flat stock (one for each surface) should be utilized and welded together where they join. The web reinforcement should be a minimum of 76.20mm (3.0 inches) high and have a 63.50mm (2.5-inch) radius at each of the two corners.
7. Completely clean the surface of frame under and around the reinforcements.
8. Clamp the reinforcements securely to the frame prior to welding.
9. Weld the reinforcement all around after welding the crack V-slot.
10. The flange edge weld should be ground smooth after all pit holes have been filled by the weld.
11. If a damaged bolted-on frame bracket is to be replaced, the new bolts, washers, and nuts should be of the same specifications and bolt torques as the original parts.
12. In cases where it is necessary to remove rivets, replace them with Property Class 9.8 metric (Grade 8 ) nuts, bolts and washers of the next larger size (i.e., for 3/8-inch diameter rivets use 7/16-inch bolts, for 7/16-inch diameter rivets use 1/2-inch bolts). This requires line drilling of the holes to the same diameter as the new bolt (i.e., either 0.437 diameter or 0.500 diameter).

Frame Member Replacement

If a damaged frame member is to be replaced, new bolts, Property Class 9.8 metric (Grade 8 ) fasteners and rivets required for replacement of parts should be of the same specifications as the original bolts or rivets. In cases where it is necessary to substitute a bolt for a rivet, use the next larger size bolt. .."

====
Swiss-Cheese Frame pic; "...'80-81 Broncos only..."
Source: by Steve83 (Steve, That dirty old truck) at SuperMotors.net
Swiss-Cheese Frame ; the very early 80's broncos have the gay swiss cheese frames with the huge holes in the end. if you were doing a leaf sprung swap, i can't imagine how you would realistically do it safely...AFAIK, the 80-82 (not sure on the year that they stopped this) had the swiss cheese frames; they are called that because there are large (like 2" or bigger if my memory serves me) holes drilled in the frame rail ends. they were to make it "lighter and more fuel efficient." also, the only place i know of where the frame was boxed was right around the engine crossmember and where the steering box attaches. i think that the 83-91 have the better frames because the 80-82 are the swiss cheese and the 92+ have the crumple zones..."
Source: by Andrew K (Andy351, das panzer, sloppy seconds, the magic carpet) at FSB
========

Frame Rivet TSB 97-4-7 for 80-96; Damaged or loose frame rivets should be replaced with approved service bolts. WELDING IS NOT ACCEPTABLE
Source: by Ford via miesk5 at http://home.comcast.net/~miesk5/technical_service_bulletins.htm#technical_service_bulletins.htm
==


etc.
GL!:thumbup
 

·
Former owner of Shadofax
Joined
·
17,038 Posts
as far as the rivets go, you really are only needing to focus on the ones used to tie to the engine crossmember. With coilovers if you remove the stock coil tower, well, those are also riveted. But from a frame strength standpoint it's just those rivets for the crossmember I'd focus on based on your intended use (I didn't mess with most of mine, but I'm not high-speeding, desert running/pre-racing mine either). that early 80's frame is the only one to avoid. I'd avoid frames from back east that are eaten up with rust as well. The newer model broncos equipped with the big-heavy E4OD also have a frame reinforcement piece just above the tranny area.
 

·
Registered
Joined
·
157 Posts
It's only the 80 frame that has the extra holes. The frame is still strong, you just need to plan your mods a little more. All the manufactures started doing the same thing to frames in later years. I have a neighbor that has a later model Chevy 2500 HD crew cab long bed 4x4 that the frame has the exact style of construction as my 80. The holes don't really take away from strength because the frames are designed to flex. The manufactures are doing this to help save weight to help mileage.
 

·
Registered
Joined
·
157 Posts
The real late model frames are hydroformed. Look at frames in the 90s and early 2000s before they started using hydroforming for the frames and you'll see that they have holes specifically for reducing weight. Shadowfax, you quoted earlier in this thread that you believe it wouldn't be safe to use leafs on an 80 for a SAS. Why? The big holes don't even start until the trans crossmember and continues on back to just in front of the shackle hangers. The front of the frame is the same as the later models with the exception of the accordian frames.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #10
Thanks guys. . .especially all that info Miesk5. . .I'm printing that up and checking the site out.

Sounds like I should be looking for a 90's frame with an E40D tranny. . .was this tranny available with all engines in 4x4 or only the certain ones?

Thanks!
 

·
Former owner of Shadofax
Joined
·
17,038 Posts
The real late model frames are hydroformed. Look at frames in the 90s and early 2000s before they started using hydroforming for the frames and you'll see that they have holes specifically for reducing weight. Shadowfax, you quoted earlier in this thread that you believe it wouldn't be safe to use leafs on an 80 for a SAS. Why? The big holes don't even start until the trans crossmember and continues on back to just in front of the shackle hangers. The front of the frame is the same as the later models with the exception of the accordian frames.
:tinfoil

can you point me to where I mentioned that, not finding it.


As I recall, having been an auto broker in the late '90's, that the chevy trucks were already using hydroforming and boxed frame. It's something they touted over ford/dodge. Point being that a boxed frame can take a considerable amount of hole punching vs. C channel, so hopefully you're not confusing a boxed frame for a C channel with too many holes.
 

·
Former owner of Shadofax
Joined
·
17,038 Posts
Thanks guys. . .especially all that info Miesk5. . .I'm printing that up and checking the site out.

Sounds like I should be looking for a 90's frame with an E40D tranny. . .was this tranny available with all engines in 4x4 or only the certain ones?

Thanks!
If you want to go beyond the frame discussion and move to trannies, it seems to me a manual would be better for you with the pre-runner setup. The 90's E4OD is a heavy auto (partly why they added to the frame). fine overall tranny but if I wanted more nimbleness I'd probably get a manual and then swap to the very strong zf5.
 

·
user title
Joined
·
2,211 Posts
[hijack]
pics of the Jeep needed
[/hijack]
 

·
Registered
Joined
·
52 Posts
Joe,
I have never had many problems taking rivets out. I use a Snap on air chisel or other very strong air chisel model. Buy a good set of bits (snap-on) make sure it is sharp and you have an adequate air supply and you will cut through the rivets like butter. Change out teh chisel for teh punch and punch the rivet out when the head is cut off. With a sharp bit you can cut teh rivet head off in a about 10-30 seconds. Works like a champ. As for a pre runner I would look for a truck with a 351 and an E4OD with a manual 1356 transfer case. I would stay away from the manual trans unless you like rowing. The 302 is just a little under powered from the factory. Check for cracks around the doors and rust at the tailgate. Meisk5 has a great website with a ton of factory info. Great resource.
 

·
Registered
Joined
·
157 Posts
:tinfoil

can you point me to where I mentioned that, not finding it.


As I recall, having been an auto broker in the late '90's, that the chevy trucks were already using hydroforming and boxed frame. It's something they touted over ford/dodge. Point being that a boxed frame can take a considerable amount of hole punching vs. C channel, so hopefully you're not confusing a boxed frame for a C channel with too many holes.
It must of been another thread that I confused the SAS with. I had a 90s Chevy along with several friends and family members and along with being under countless others as the former mechanic turned neighborhood mechanic. I know what hydroformed and c-channel is considering I went to college for mechanical engineering. I also never said the c-channels were as strong as boxed. I just said that they are not lacking in strength. Too many holes will weaken anything, but the 80s Broncos don't really have that many holes. The holes are strategically placed to reduce weight without giving up much strength. I apoligize for the confusion about the SAS statement.
 

·
Registered
Joined
·
51 Posts
Discussion Starter #16
these trucks are rivet nightmares
Great to hear. . .the Willy's was a NIGHTMARE!!!

[hijack]
pics of the Jeep needed
[/hijack]
I'll post some links to the build threads. . .this was my first 4x4 build and my first from the ground up build (even though it isn't done yet) so there are a LOT of things I would do differently the next time around and a LOT of things that I'm gonna improve on this project as well. . .

Joe,
I have never had many problems taking rivets out. I use a Snap on air chisel or other very strong air chisel model.
There would be a key reason. . .you have pneumatic tools and I did it by hand with a 4 1/2" angle grinder, an engineer's hammer, and a punch!!!!

Took a LOT longer than 10-30 seconds to grind the head off (without grinding into the frame) and even longer (and more manual effort) to drive them out once the heads were ground off!!!

As for a pre runner I would look for a truck with a 351 and an E4OD with a manual 1356 transfer case. I would stay away from the manual trans unless you like rowing. The 302 is just a little under powered from the factory. Check for cracks around the doors and rust at the tailgate. Meisk5 has a great website with a ton of factory info. Great resource.
Thanks for the tips. . .I'm a big manual guy, but I'm beginning to see the benefits of a built auto for off-road use. . .

. . .auto's have come a long way and it's one less thing to think about when trying to concentrate on the course and the lines. . .although you still give up the fine control that you have with a manual, not to mention the ever present (no matter how small) lag between throttle input and actual motion. . .but you don't have to worry about stalling out. . .oooohhh choices, choices, choices!!!

If you want to go beyond the frame discussion and move to trannies, it seems to me a manual would be better for you with the pre-runner setup. The 90's E4OD is a heavy auto (partly why they added to the frame). fine overall tranny but if I wanted more nimbleness I'd probably get a manual and then swap to the very strong zf5.
Like I said I love to row gears, but I think that I like it on the asphalt track more than offroad!

What auto tranny would guys suggest for offroad use behind a stroked and bored Windsor. . .somewhere in the 400 CID range???

Thanks for all the tips!!!
 

·
Registered
Joined
·
32 Posts
center punch your rivets, drill half way through working up from a small bit to about 7/16 or half inch. punch the rest out. real simple
 

·
Registered
Joined
·
204 Posts
I had to repair and add a gusset to my frame at the steering box it cracked and got a death wobble. Crossmembers like my rear shock tower help. Has anyone done anything or know of aftermarket skid plates?
 
1 - 19 of 19 Posts
Top