Farmer Joe Posted January 23, 2009 Report Share Posted January 23, 2009 was wonderin if 521 and 620 upper and lower control arms were the same. im wanting to make some control arms so i can run balljoints and 84up 720 spindles and brakes. thanks Quote Link to comment
BEEBANI Posted January 23, 2009 Report Share Posted January 23, 2009 They are the same. I make upper arms for doing just what you wanna do. Quote Link to comment
Farmer Joe Posted January 23, 2009 Author Report Share Posted January 23, 2009 how much do you sell a set of those for? what would i do about the bottom control arm? can you swap the lower control from a 78-79 620 to a drum brake truck? Quote Link to comment
]2eDeYe Posted January 23, 2009 Report Share Posted January 23, 2009 That's exactly what you do. Easy swap to disc brakes, you need the lower control arm, spindle, hubs and brakes from a later model truck. I would suggest using at least an '85 (I think) or newer control arm/brake combo. This way you get vented rotors and the newer style calipers Quote Link to comment
Farmer Joe Posted January 23, 2009 Author Report Share Posted January 23, 2009 so a lower control arm from a 84 and up 720 will bolt on to the 620 frame? if thats so, then things just got alot easier. mmmmm disc brakes would be oh so nice!! Quote Link to comment
BEEBANI Posted January 23, 2009 Report Share Posted January 23, 2009 Yeah, the 720's will bolt right up to the 620 frame. These arms will allow you to keep some adjustability with the added width of the 720 lowers. The 720's had a wider track width, and the 720's/hb's mounted the upper arms on the outside of the frame instead of the inside like the 620's do. I sell these for $150/pair. Quote Link to comment
SHADY280 Posted January 23, 2009 Report Share Posted January 23, 2009 i have a set of beebani's arms and they are very very nice. i got them powder coated and the bushings in and ball joints installed, just need to put them on the truck. still waiting for the dang hubs to get machined. Quote Link to comment
Farmer Joe Posted January 23, 2009 Author Report Share Posted January 23, 2009 mkay. how much wider is the track width on the 720? cant be much can it? also, will the 720 tierod work with the most of my stock 620 steering equipment? thanks for the help. finding out all this stuff will make swappin the brakes alot easier. Quote Link to comment
SHADY280 Posted January 23, 2009 Report Share Posted January 23, 2009 keep your stock steering i believe. at least on mine, cant imagine the 521 is different. once i eventually get it installed there shall be pix. Quote Link to comment
yello620 Posted January 24, 2009 Report Share Posted January 24, 2009 mkay. how much wider is the track width on the 720? cant be much can it? also, will the 720 tierod work with the most of my stock 620 steering equipment? thanks for the help. finding out all this stuff will make swappin the brakes alot easier. Track width is about 2.250" total increase, 1.125" per side. The lower arms are not a direct swap, you have to weld spacers onto the arms at the frame mounting bolt. You need two 1/4" spacers for each control arm. And you have to modify the tension rods to fit your frame. my 620 tie rods fit right into HB spindles. I dont know what the 521 has for tie rods. On your 521, you are going to want to address the single reserivoir master cylinder too. Quote Link to comment
Farmer Joe Posted January 24, 2009 Author Report Share Posted January 24, 2009 i dont have a 521. i wish lol... so what about lower control arms from a 620 that had disc brakes? could i run the 84 and up spindle on those? Quote Link to comment
Guest DatsuNoob Posted January 24, 2009 Report Share Posted January 24, 2009 Track width is about 2.250" total increase, 1.125" per side. The lower arms are not a direct swap, you have to weld spacers onto the arms at the frame mounting bolt. You need two 1/4" spacers for each control arm. And you have to modify the tension rods to fit your frame. my 620 tie rods fit right into HB spindles. I dont know what the 521 has for tie rods. On your 521, you are going to want to address the single reserivoir master cylinder too. What do you mean by spacers, can you show a picture, sorry, I'm a visual learner:D. I'd like to know so when it comes time, I know what to expect. I've been putting my conversion off for too long. I've just been too busy at work, and too lazy at home. Thanks man. Quote Link to comment
BEEBANI Posted January 24, 2009 Report Share Posted January 24, 2009 Good to know Jason, I calculated about 1.5" per side (this was by comparing hubs/spindles from both trucks) I didn't know about the 1/4" spacers as I modded the 620 lowers to work with hb spindles on my truck. Farmer-all the tie rods have the same tapers on them, I'm currently running all 720 tie rods on my truck right now. Noob-the 720/hb lca's have a wider mount where they mount to the frame than the 620's, so spacers are required to keep them tight to the frame. Quote Link to comment
yello620 Posted January 25, 2009 Report Share Posted January 25, 2009 Good to know Jason, I calculated about 1.5" per side (this was by comparing hubs/spindles from both trucks) I didn't know about the 1/4" spacers as I modded the 620 lowers to work with hb spindles on my truck. Farmer-all the tie rods have the same tapers on them, I'm currently running all 720 tie rods on my truck right now. Noob-the 720/hb lca's have a wider mount where they mount to the frame than the 620's, so spacers are required to keep them tight to the frame. Beebani I didnt do the measuring for the 1.125" myself, so you could be correct on the 1.5", But i dont think that i gained that much on my truck. And those spacer apply to the 78/79 620 lower disc arms also. Quote Link to comment
Hyphy Posted January 27, 2009 Report Share Posted January 27, 2009 was wonderin if 521 and 620 upper and lower control arms were the same. im wanting to make some control arms so i can run balljoints and 84up 720 spindles and brakes. thanks heres the confusion ... The mentioning of a 521.. Since the 521 is a kingpin setup, will these arms still work? I dont mean to hijack the thread, but ive been seeing the balljoint swap stuff floating around and thought id ask here where the guys that have done it are. Seems this thread is mainly bout the 620 tho Quote Link to comment
BEEBANI Posted January 27, 2009 Report Share Posted January 27, 2009 620 is a kingpin setup also, that's the reason for the swap. Yes, it will work to answer your question. Quote Link to comment
Farmer Joe Posted January 28, 2009 Author Report Share Posted January 28, 2009 does anyone have a pictures of the torsion bar mount for the lower control arm for a 620 and a 720? i wanna see what the difference is between them. thanks! Quote Link to comment
yello620 Posted January 28, 2009 Report Share Posted January 28, 2009 does anyone have a pictures of the torsion bar mount for the lower control arm for a 620 and a 720? i wanna see what the difference is between them. thanks! No pics, but the torsion bar mounts are different for king pin arms versus disc brake arms. But the spline count is the same, so make sure to get the torsion mounts with the lower arms. Quote Link to comment
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