Disk Brake Conversion

[69Rob]

Ok i know there is always question on this but could some one help me out with the conversion. I got a 69 LWB and im going to be placing disk brakes on it. I got the whole front suspension off a 81 truck power gearbox, front cross member booster every thing and a 3 row radiator for 300$ i really dont want to trade out the whole member just the parts so my question is which parts are the main ones can i keep my c-arms? the master cyclinder is different though its the plastic one will it work? will there be any major adjustments i will have to make? sorry for the questions but any advice would be so helpfully.

[69gumby]

Man I just don't know about a front end that new. On another thread we have been talking about 71 and 72 front ends bolting on with no problem.

[69Rob]

i was told that a 73 through a 87 would work the 71 and 72 i would have to change my outer rods plus a couple other things. this way i have every thign i need so alli can got to buy is the new ball joints and im good but i think the used ones are still ok

[ERASER5]

Is your engine in or out? Are you wanting to have all new parts? Or are the ball joints, tie rod ends good enough on the '81 parts? These answer will determine what you keep from the '81 stuff.

If your engine is still in, swapping the cross member is not really an option.

If you want all new joints, bushings, calipers, rotors, pads, then swapping the cross member is a wast of time.

The parts you need to keep are the A-arms, spindles, and the drag link. The springs are up to you. The newer springs will lift your truck some. The A-arm bushings are most likely OK. Finding someone that is willing to change them is tough too as bending the arm is a problem. New '81 brake parts will work just fine. Order ALL parts for the same year! You may need to re-route the hard line/flex line connection. The MC may work, but the booster could be a problem. Our boosters use a linkage between the fire wall and the booster to set the pedal leverage.

Last, but not least, are you going with 5 or 6 lugs? Is the '81 rotor 1" thick or 1.5"? The 1.5' is the HD brake and is the desired setup. The 5 lug rotor is standard off the self and can be had as standard or HD. If you want a 6 lug, you have to have the HD setup and order the rotors from an aftermarket company like McGaughy's, or Early Classic.

Going with all new parts will cost you about $1K including the $300. BUT you will have a completely NEW suspension.

On the other hand a friend of mine just used all the late model parts "As Is" and did OK. He later had to replace the rubber brake lines. So he has about $20 plus the cost for the complete junk yard front end. Your choice.

The radiator is another matter. I have no idea if it will fit.

[70GMCer]

This is what I used on my conversion back in the Spring. 1984 1/2 T spindles, center drag link, inner & outer tie rods. I stayed with my original upper & lower control arms, but changed the ball joints for a 73 - 87 1/2 T trucks/suburbans. I wanted to stay with the 6 lug setup, so I bought a 6 lug rotor kit from JMCPauls, kit #658294 for $275. It comes with everything you will need to complete the job. Here's the link. http://gmcpauls.com/Brakes&Steering.htm JMCPaul uses the same quality brand named parts as the higher priced truck suppliers do, & he is also a site supporter.

The whole disk swap cost me around $450 including new outer tie rods & brake lines from the front to the rear. Now keep in mind, that I already had the suspension parts that I had got for free. You can change out the whole front xmember with the engine installed in the truck, but you will have to disconnect the motor mounts & lift the engine before dropping the old xmember. That is one reason I did just the parts swap.

The reason I stayed with the original controls arms, is that the 73/87 lower arms will not clear "Hedmen" long tube headers for a sbc engine. I don't know about other headers if they will clear or not. Also pay special attention to the way the center drag link is taken apart. If you put it in backwards, & it is easy to do, the front end will not align up.

As far as the power booster, I had already had the power booster from a 72 3/4T installed. Not sure on the fit of the later models. Also remember to install the Proportioning valve from the doner truck. That is for disk brakes.

There are plenty of write ups about this subject on this site & in the FAQ section.

[69Rob]

i cant belive i forgot to check if it was 5 or 6 lug i was just excited i was getting the parts and for got the basics all the bushings on the donor parts are still good i plan on chaning them when get he cash set up now if it is a 5 lug can i get the rotors at a local auto store for 6 lug and still work with the rest of the stuff?

[Elephanthead]

I have a question, I have a 67 1 ton with manual steering, will later ball joints fit in the a arms, so I can install junkyard spindles and dually front rotors? I plan on using late model outer tie rod ends with an after market adjuster to join it to the inner. Also it has manual brakes, what are my options for keeping them manual, I know the discs need more fluid to operate, probably more then the stock master can supply.

[70GMCer]

Originally Posted by 69Rob

i cant belive i forgot to check if it was 5 or 6 lug i was just excited i was getting the parts and for got the basics all the bushings on the donor parts are still good i plan on chaning them when get he cash set up now if it is a 5 lug can i get the rotors at a local auto store for 6 lug and still work with the rest of the stuff?

Trucks went back to 6 lug in the early 90's. There have been a lot of right ups on using them on earlier spindles. The consensus is NO they will not work. The bearings are off set & will not mate to the early spindles. Again, this is what I have read on here. I didn't want to spend a lot of time trying this & that. So, that is why I bought a proven kit to use. When you are talking brakes & steering, don't take chances on using something that "might fit".

[69Rob]

ok well im going to go pick the parts up today so im planning on doing liek you did 70gmcer im going to get the outer-inner rods and the spindles plus the drag and buy a kit most likely from puals but should alos get the booster and mc or just hold off and try and find one from a 72 or so?

[69Rob]

so does any one know if the 81 booster will work withoutout any major mods?

[69Rob]

any one?

[69Rob]

Does any one know what 6 lug rotors i can buy at a local auto store that will work with the disk setup i bought from a 81 chevy pickup?

[hotrod 80]

There is a thread in the FAQ section on making the M/C , booster work . I don't believe you will find 6 lug rotors for a 73-87 unless they are from an aftermarket supplier .

[ERASER5]

There are no 6 lug 1.25" (HD) at your local parts store. There are no 1" 6 lug aftermarket rotors that I am aware of. The McGaughys can be gotten from McGaughy's, GMCPauls, and other site venders. CPP will have some version as will ECE.

The '81 booster can be used, but will take some work to get it right. It will not just "slap" on and be correct. Someone has done it.

The correct booster setup can be had from GMPauls as well. Check the prices against what it will take to get the '81 booster to work.

Make sure that the rotors on your donor '81 are the 1.25" HD version.