1970 521

[wayno]

I do have a question though, I'm wondering does anyone know if the front suspension mounts are the same as a 620? What I'm getting at is can I put on 620 control arms, spindles, and most importantly, the disc brakes in the front? Then swap out the master, put in a proportioning valve and have front disc brakes?

 

 

No, they will not just swap over, but I beleave the 620 regular cab short box frame is within an inch of the 521, so you can just swap the cab and box onto the disc brake frame with a little effort.

What you are asking about above can be done with a lot of modifications, as I have done it, but I would never do it again, I would just swap frames, it's just safer.

[devilsnake98]

Ok thanks for the reply, you bring up safety, I can imagine its a matter of splicing the two styles of arms together then plating them for strength? Just thought I'd ask cause front disc would be heavenly. Are the frames different in an area that is important? Or just a trim or move something this way or that way a little?

[jrock4224]

anyone else wonder why royal has been on ratsun several times and posted but never came in here and posted......yo royal whats up ...lurker..

[jrock4224]

devils ..... use google to search (ratsun search bar sux...)... and add ratsun .net to the end if you need to research stuff... theres a ton of info out there on similar mods....i looked into 620 front end but decided in the end the king pin is fine and durable especially with a brake up grade...wih plans to bag mine king pin front ends dont bind much...

[wayno]

The lower 620 control arm(LCA) will fit where the 521 arm is, but the bushing is narrower so washers would have to be used to take up the slop, or a 620 bushing would need to be pressed into the 521 frame.

Then the upper control arms(UCA) would need to be lengthened about 3/4 of an inch, I found it to be easier to buy two sets of 720 upper arms and cut them in such a way that when welded together they would be the correct length.

Next you should drill the UCA mount holes out and tap them to accept the 720 UCA mount bolts, I did not do this, and them bolts have broken on me several times, lucky I have not been moving faster than 30mph when they have broke, it could get REAL UGLY FAST if you were driving down the freeway.

This is important, when you install the UCAs, you must put the right side on the left, and the left side on the right, as this gets the upper balljoint back where it needs to be.

If this post has not convinced you not to do it, PM me and I will scare the shit out of you.

 

Check this thread out in the link below.

http://community.ratsun.net/topic/8175-mklotz70-project-mend/

And this one also.

http://community.ratsun.net/topic/11459-disc-brake-kits-521520320620/

He might be making something you can buy and bolt on.

[skyblue]

welcome and congrats on the new purchase. I've always liked this truck and I'm glad it didn't end up in the scrap yard.

[jon521]

^true story^

[devilsnake98]

Thanks for all the info wayno, I'm a fabricator on the side but when it comes to stuff like hacking up and splicing control arms, I'll pass. I'll either look into a 620 frame, or do a disc brake conv. On my kingpin front end like in the posted link. I have been looking at this truck for a while, seen it on Craig's when it was for sale in Seattle with the goofy rear suspension, and all the times royal posted it for sale. I tried to buy it then but never could get through, then finally seen it for sale again a week ago and pounced on it. It will definently NOT be going to the scrap yard.

[wayno]

Thanks for all the info wayno, I'm a fabricator on the side but when it comes to stuff like hacking up and splicing control arms, I'll pass. I'll either look into a 620 frame, or do a disc brake conv. On my kingpin front end like in the posted link. I have been looking at this truck for a while, seen it on Craig's when it was for sale in Seattle with the goofy rear suspension, and all the times royal posted it for sale. I tried to buy it then but never could get through, then finally seen it for sale again a week ago and pounced on it. It will definently NOT be going to the scrap yard.

 

So you bought this truck, have you done any work on it yet?

[devilsnake98]

Nothing substantial, just pulled the seats to clean out all of the garbage that was inside and scrubbed down the floor. I'm gonna start on the engine this weekend and figure out what it needs.

[banzai510(hainz)]

if you want disc I would go with Mklotz set up as it all engineered up already and cost should be resonable.

 

However I know this truck when Joe(zuum510) had it. Matter of fact I belive I have the 4 speed out of it and its in my truck now.

Then Eric Long had this and We replace the clutch master and slave at my house.

Its an OK under 1000$ truck.

But I would NOT do a frame swap and all that other bullshit on this truck. There are better 521s out there you could do all this fancy stuff on.They do show up. for 1500$

To me this 521 had to much bubbled rust lurking under the paint. that will come back.

 

I would just keep it close to whats goin on make it relaiable. Eric pretty much had it as a daily driver and ran good with the l20 for awhile.

 

The chevy rally wheels did make it look good.

[devilsnake98]

I do see some slight rustissues on both the body and the floor, but it's nothing that some time and sheet metal won't cure. I'm gonna do a once over everything this weekend and see what all its gonna need. I don't want a show stopper just a cool driver, so going nuts isn't in the future. Did get another set of chev rally's for it today though.

[jon521]

so wait, did you buy it from royal or from someone else? did you change the headgasket on it?

[devilsnake98]

I bought it from the guy nick who bought it from royal. Nick did the head gasket but I don't trust it and its down a cylinder, so I'm gonna re-do it and have the head gone through by ricks cylinder head service in oak grove.

[jon521]

ah ok. well im glad it went to a good owner!

[devilsnake98]

Got a chance to put some time in on the 521 over the holiday weekend. Did a comp test and found #1 cyl only has 45 psi, while the rest are 120 125 and 140, which is an obvious reason for my weak cyl/ misfire. Also checked out the suspension and wasn't real impressed. Sitting on bump stops in the front and still some shady stuff going on in the rear. So I will be saving up some bucks to get an engine rebuild kit, get it running good again, then dive into the rest after that.

[banzai510(hainz)]

I would pop open the crank case vent tube and at idel see/smell if excessive blowby. Im thinking you should.

 

would have been nice if the guy who did the headgasket ck the valves for cracks or anything. Maybe all that needed is a head swap. if bottom ends apprears good.

 

going with 15s and a 50series tire you really got to lower to fill in the tire whell. That why I stay with stock overall height tire to give the appearance of MOAR LOWER.Im 195 /65/15 when I had 15

I run stock rims with hubcaps

 

you can remove the rubber bump stops and hope it doesnt hit the frame

[devilsnake98]

Ok, I'll look into the blow by it has this weekend, hainz do you have a pic of a 521 with the 195/ 65 15? i was actually thinking of raising the tire sidewall profile then raising the suspension to get some travel back.

[wayno]

As I said before, I have most of what you need to put it back to stock in the rear, I have two rear section frames out back complete, and one still has the shocks and rearend mounted, but this would be something that you would have to come here to do.

[konig209]

Since the rear end was brought up here is mine. Haha

 

 

on another note i got an issue. I dog track....alot :-/

I was under it the other day and noticed that there is a small gap between shock and axle and the orher is rubbing against the axle.

[wayno]

Since the rear end was brought up here is mine. Haha

 

 

on another note i got an issue. I dog track....alot :-/

I was under it the other day and noticed that there is a small gap between shock and axle and the orher is rubbing against the axle.

 

Sometimes the blocks have several holes in the bottom of them, are they in the same holes on both sides?

To see which wheel is out of center, stand to the side of the truck, and look at which wheel is out of center in the wheel well, and move that one forward or back.

[I'm BLUE]

In addition .. check your leaf spring bushings.

Make sure leaf spring locating pins are intact.

Hope it wasn't in a previous wreck.

 

I once drove a truck that had nearly rusted off shackles ... It was a hoopty ride hahah.

[oldskoolvws]

Did you do a wet compression test with oil? This will tell you if its pistons or head.

 

195/50/15 on 15x8

[konig209]

 

 

Sometimes the blocks have several holes in the bottom of them, are they in the same holes on both sides?

To see which wheel is out of center, stand to the side of the truck, and look at which wheel is out of center in the wheel well, and move that one forward or back.

ding ding ding your right about a wreck......but the bed is moved so i cant test your method. The gap between the bed and cab on passenger side is smaller than driver side.

Sorry for thread jacking.

[devilsnake98]

Oldskool- I did the comp test with and with out oil, it went up after the oil was there, leads me to believe the rings are worn or a broken. And is you're truck on the bump stops in the front? My truck had 15x8 with 195/50 and to look right, it's on the stops.