81 Disc on a 69

[69Rob]

I was wondering if any one could help me out with this swap. i got the whole front end of a 81 and im trying to put the lines on but im having trouble getting them run. my question is will i have to make my own lines or should i be able to jsut bolt those lines right on? and doesa ny one have any pics? i got my bags in and my engine built this is the last thing i need so any help would be great

[N2TRUX]

I have never done the conversion, but as far as I know they bolt right up.

I believe you will have to adjust the brakeline brackets a bit, but that's it.

[lolife99]

Did you change the mastercylinder and porportioning valve also?

[Tx Firefighter]

The lines will lay in place, but you will need to drill 4 holes. Two to mount the prop valve to the front (under radiator) crossmember, and two in the fame rails, one per side, for the brake lines to pass through. Then, use the later model brake hoses. It will look exactly like a late model setup once done.

[SCOTI]

Originally Posted by Tx Firefighter

The lines will lay in place, but you will need to drill 4 holes. Two to mount the prop valve to the front (under radiator) crossmember, and two in the fame rails, one per side, for the brake lines to pass through. Then, use the later model brake hoses. It will look exactly like a late model setup once done.

Actually, there should already be one hole in the splash apron. I used that & drilled the second one. The frame holes are also already there (they were on my OE drum brake 68 1/2-ton).

The lines did require slight tweaking to follow the frame rail nice & square, but overall they fit w/o much fuss. I used a 71/72 master cyl & booster w/some 75 lines, prop valve, & front suspension on my stock 68 c.member.

[69Rob]

Sorry for the late response havent been on since i asked the question. i already placed the mastercylinder on and there is one whole in the splash.l im guesing im making it harder then it is i just tried again this weeken and the lines are jsut not working any one got any pics im thinking of just going to teh junkyard and taking some of my own well any ways thanks for yous response

[69Rob]

Ok i got all the lines ran and hooked up. i got 6 lug rotors off a 1990 truck my problem is that when i try and put the calipers on they fit in the spindle fine but when the the side of the caliber facing the out side is right on the rotor no room for a pad. am i suppose to buy big calipers?

[SCOTI]

Originally Posted by 69Rob

Ok i got all the lines ran and hooked up. i got 6 lug rotors off a 1990 truck my problem is that when i try and put the calipers on they fit in the spindle fine but when the the side of the caliber facing the out side is right on the rotor no room for a pad. am i suppose to buy big calipers?

I don't believe 90 rotors will work w/the 73-87 caliper arrangement. You need 6-lug aftermarket rotors. These are based on 5-lug rotors but instead of drilling them for 5-lug, they're drilled for 6-lug.

The 88 & later brake swap is 'do-able', but it requires 3/4 ton lower a-arms for the larger lower BJ needed, 88-98 spindles, & 88-98 brake related parts to complete the swap.

[69Rob]

crap i already put all new bearings had the rotors turned and got 3" drop spindels for a 81. my thing is that i matched up the 6 rotors to the 5 lug rotors and they the exact size thickness and width so the 5 lug rotors have the same problem

[SCOTI]

Originally Posted by 69Rob

crap i already put all new bearings had the rotors turned and got 3" drop spindels for a 81. my thing is that i matched up the 6 rotors to the 5 lug rotors and they the exact size thickness and width so the 5 lug rotors have the same problem

Dimensionally they should match on the exterior surfaces; it's where the bearings seat that are different from what I remember (thus, it positions the rotor too far to one side for the caliper).

Try a stock 5-lug rotor. If it fits, order some aftermarket 6-lug rotors from one of the board supporting vendors, ECE, or CPP.

[69Rob]

Ya i was thinking about that then i saw on one of the prices for $100 a rotor. Dont think i can do that for a while i guess im just going to have to ride 5 lug up front and 6 in the back

[69Rob]

ok i bought the 6 lug rotors from ccp my first order with them and they did good so far. even with the new aftermarket rotors my calipers still do not set right the only i way i can get them to work is by removing the spacer that goes with the bolt that goes through the spindle and caliper. is there any danger if i remove the spacer? the bolt holds just fine

[lolife99]

Did you know that there are two different thickness of rotors? And the calipers have to match.

What did the '81 front suspension have originally? 1" or 1-1/4" thick rotors?

What drop spindles did you order? For the 1" or 1-1/4" thick rotors?

Sounds like you originally had 1" thick rotors and calipers,... and NOW you have 1-1/4" thick rotors and your 1" thick calipers won't fit.

You may just need a new set of calipers that fit your new 1-1/4" rotors.
Any pics you can post would be a big help.

[69Rob]

when i ordered the rotors they didnt give me an option to pick so now i guess i got to make a drive and get the dims and see if i can snap a few pics if i do need 1 1/4 rotors do you kno what truck i can take them off of

[lolife99]

If you have CPP rotors,... they are the 1-1/4" wide ones.
You probably need to just replace the calipers. Your local Auto Parts store should have them fairly cheap. Also consider changing the front rubber brake hoses also.