Knocking/Thumping in front end during slow braking?

My 1992 Bronco doesn't see as much trail time as I would like and is really not trailbashed too much. Lately, I've noticed a strange sound coming from under the front end when I apply the brakes, especially in a slow turn. The best way i can describe it is a popping/clunking noise, almost like, funny as it may sound, knuckle cracking, of varying pitch depending on the speed. I've pretty much isolated it to the front linkage but where exactly I have no idea. Everything seems tight and nothing is apparently loose. Anyone have any ideas where to look further?

First off, is it lifted? If so what brand and does it have radius arms? Sometimes the front axle housing can tweak slightly when going forward and back. It is due to the radius arm being either loose, broken or weak. The housing rotates slightly which in turn binds up the forward u-joint in the driveshaft. When the housing releases/rotates back the u-joint also releases and "pops." That could be what you are hearing. Have someone go back and forth a couple feet while you watch the front axle and driveshaft. You will know it if that is your problem. This is just in the case of lifted trucks as I have never seen it happen with stock rigs.

No lift. It's strictly stock. We are going to put it up on jackstands today and try to get a better look at the linkage components.

not to discourage you but have you checked the rotors lately?
shocks?
whatever arms these cars have(my truck(78 bronco) has massive trailing arms/i-beams) to keep the suspenion/"axle" from moving fore and aft
or the bushings there of

but any decent autoparts store can check these for warpage

as you may find out 80 on broncos (and all other varihcles) have been shaved for weight and they include the critical spots i.e. thinner rotors, windsor or modular engines,body steel, frames and alot of parts that belong on a 2800lb +/- car or "mini"truck(ranger) and would fit in a good small build

afriend of mine has a 50's car and the sheet metal is very thick and not structural(uni-body) when compared to today's tissue paper thin uni-body cars you have got to be kidding me ya want how much for this death trap

as far as motors have you looked at the torque rateng on these trucks 35-3700 rpm is typical i don't about you but i prefer to put my truck in gear before then the numbers are very deceptive

well the beginning may help but i got off on a rant guess i sore about being heaped in with 80 up verihickles sorry**frowny face**

p.s. wonder where the new "trucks" are gonna be in 24 years(the age of my truck)

crap another idea check for a bent shock/stut rod

when you brake more weight compresses the front susp

Well...I pushed, pulled, tugged, kicked, spun the axles, etc, etc. This totally baffles me. The idea about the ujoints on the front axles made sense so we looked at that really hard...no apparent problems there either. I converted to manual hubs a long time ago, with them "free spinning" I don't even think my axles/front drive shaft is rotating unless I'm locked in 4wd, or at least there is no indication of it. It's going back up on the stands this weekend and I guess we'll start turning wrenches. A friend of mine suggested the balljoints on the spindles, does this make sense to you guys?

Did you check the radius arm bushings? If they are bad they can cause a bumping/clunking sound like you said. Also check the body mount bushings in the fromt.

Fixed!! Of all things, apparently a brake job on the front, plus I snugged up the front body bushing bolts just a touch. The front brake pads were, in an understatement, THIN! I never really saw where there would be room for them to clunk around but I do believe that's what I was hearing. Funny thing is, they never really squealed or were mushy to tell me I might need brakes. Oh well, lesson learned. Thanks for all the help.

Good to hear.