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Difference btw '85 vs '87 14bff for disc swap?

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Ned Kelly

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Ok, from what I understand, 1985 and older 14bff are the one's to get for a disc brack swap. 1987 or so the 14bff went to some external way to mount the drum onto the spindle or hub ?(DIY.com kit will not fit these). So basically one would want to get a 1985 or older 14ff if contemplating a disc swap. I noticed on a 1988 K30 14ff has some ribbing on the back of the center section. My 1985 doesn't.Is there any way to externally tell if a 14bff is the new style vs the old?
 
The ribbing that you mention is a good indicator of the newer style. That would be the one you don't want. I've seen a couple 86's with the newer axle in them so somewhere in those years that start switching them out.
 
Ned Kelly said:
Ok, from what I understand, 1985 and older 14bff are the one's to get for a disc brack swap. 1987 or so the 14bff went to some external way to mount the drum onto the spindle or hub ?(DIY.com kit will not fit these). So basically one would want to get a 1985 or older 14ff if contemplating a disc swap. I noticed on a 1988 K30 14ff has some ribbing on the back of the center section. My 1985 doesn't.Is there any way to externally tell if a 14bff is the new style vs the old?
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The info on these is so poor. :screwy:

My '91 V3500 has the same hubs/drums/spindle as the older stuff.... only difference is the ribbing on the center section. The 'new' style (92-up?) has the slide-off drums. Only applies to the SRW axles though.
 
I am using a 14-bff from a 91 Suburban (it has the ribs on it that were mentioned). The hub and brake setup is the same as an mid 80s van 14-bff that I have. I did a disk brake conversion using parts from another vendor, but everything bolted up.
 
djohnsn said:
I am using a 14-bff from a 91 Suburban (it has the ribs on it that were mentioned). The hub and brake setup is the same as an mid 80s van 14-bff that I have. I did a disk brake conversion using parts from another vendor, but everything bolted up.
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Hmmm, did you or a previous owner swap that 14 Bolt FF in the 91 Burb? The largest axle to come in the rear of a 91 Burb was the 14 Bolt Semi Floater.

Eric M.
 
the 14ff sittin in my backyard is out of a 88 burban. It has the ribbed center section and the old style drums. I believe the FF came in the burbans if it had a 454.
 
k20 said:
the 14ff sittin in my backyard is out of a 88 burban. It has the ribbed center section and the old style drums. I believe the FF came in the burbans if it had a 454.
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That makes sense. But only 2 wd Burbs came with 454s (from the factory) up until 92. So I guess 2wd, 3/4 ton Burbs with 454s had 14 Bolt FF rears. Does that sound about right?

Eric M.
 
The kit I bought from TSM was originally installed on a 85 14ff. I recently swapped in on a 88 14ff with the ribbed centersection with no problems.
 
Do you think the DIY kit was referring to the 14 Bolt Semi Floater as the unit their kit would not work on?

Eric M.
 
So at what point exactly did they start doing the drums/hubs the other way? My friends crew cab has them the new way and the spacing is wrong. Maybe the indicator here is the anti lock brake system. His is anti lock brakes. I wish I had time to just go through the yards and get some facts cause all the books I have looked in for the info disagree with each other as to what actually changed and when. I'm afraid I would find more questions than answers.

Bottom line is if your brake drum is behind the hub the brake conversion kit will work.

If your brake drum is ready to come off when you remove the wheel the kit might not work. I still don't see why you can't push the studs out and put a rotor behind the hub the way the older ones are. Unfortunately I don't have a newer style one around to check that on except for my friends crew cab and I don't want to mess with his anti lock brakes. Maybe its the WMS on the hub itself. Not lending itself to having a wheel sit against it???
 
I pulled the 14-bff from a suburban in a junkyard, so I don't know it's history. Everything about the truck looked original though. The suburban was marked as a 91, but I guess that I don't know for sure. It did have the 89-91 front clip, body side moulding, and electric mirrors.
 
i am going to do this soon but need to get some time and mesure stuff. if it works and is easy fix for any problems i will post up the info.
 
dyeager535 said:
According to TSM 14FF year split '86+ were different.

Not saying their right of course, I just recalled seeing that before.
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Yep, I read that as well but know for fact I've seen 87's with the old style yet. I believe the phase things in slowly so you have some old and some new style axles on the same years. Why do they do that? Must be so you can yell at the parts counter guy when he gives you the wrong parts. :grin:
 
i have read that the pop off drum setup stlye hub needs to be cut and some work done to it if you use the rotor on the back side. this was from a ord kit if i remember correctly. thay had a core charge on them so thay could do this.
 
cybrfire said:
I still don't see why you can't push the studs out and put a rotor behind the hub the way the older ones are.
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Because the backside of these hubs is not machined flat.

You say your buddy's crewcab is the newer body... that means its '92 or newer... which jives with the info I already posted. Crewcabs also didn't come with any kind of ABS until '92.
 
I figured it was something like not being a trued surface.
 
i have an 86 k30 reg cab and an 87 crew cab and they both have the same older style rear axles
 
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