Q: Upgrading to Disc Brakes (Forgotten Tasks)
I just picked up the whole front disc components off of a 1969 ‘bird to put on my 1968 with drums in front. It came off of a working (stopping) car. I have a non-power drum all the way around on my 1968.
Besides new pads, is there anything that i should do to the booster or master cylinder to ‘freshen it up’? Is there anything inside the booster that needs a new seal or anything like that? There is a white plastic bushing ‘thingy’ that sleeves over the rod that goes into the back of the booster that is in pretty sorry shape. Is this something that I can replace easily and inexpensively? I plan on getting the rotors turned for about $7 each at Kragen. Anything else I should do to have essentially ‘good as new’ brake components???
The whole unit is pretty cruddy (grimy/rusty) and could use being cleaned up and painted. Any good ideas of what and how to clean it up with? How about paint? Regular enamel do okay?
By the way, I noticed that the rotors on one side came from a wrecking yard (telltale markings of painted numbers)and has a groove in the middle of the rotor that obviously came manufactured that way. What is up with that??? Used for cooling on another vehicle maybe?
As far as the proportioning valve is concerned, will this need to be adjusted if it already came off of a 1969 with discs in front, drums in rear?
A: I’d consider performing a vacuum test on the booster. If it leaks, you can then use it as a exchange core. You can wire brush the rust and crud and paint the booster. Eastwood sells a paint kit that reproduces the cad. look. But it is my understanding that silver cadmium was in fact the correct color. Most lower priced rebuilt units are painted (black) and not plated. You can get a rebuilt unit plated for extra money. I did this.
If it were my car, I’d probably use the master cylinder and calipers as core exchanges as well. This way you have reliable rebuilt or new parts for these critical items. If the caliper pins/bolts are pitted or badly rusted, get rid of them. You should be able to find replace- ments at a good auto parts store. Look at the HELP! brand display. Dump the flex lines since they are old and will most likely fail when you most need them. New brake hoses are not terribly costly.
As for things like brackets and spindles, get them hot tanked at your local machine shop. See if they will bead blast them for a reasonable fee. I did this and found the cost reasonable. This leaves a surface perfect for painting. You can then paint using your favorite system. I used POR-15.
I’ve seen original style 1969 rotor with that groove, and replacements without it. The original rotors are 2 piece. They rotor itself bolted to the hub. They are hard to find, and are costly. Most replacements are 1 piece, less expensive, and your car won’t know the difference. 1969-72 Nova/Chevelle/LeMans/Omega/Ventura/Skylark will interchange, among others. I have no idea what the groove was for.
The stock proportioning valves are non-adjustable. You must get the disk brake unit from the donor car, or buy a new one from someone like Master Power Brakes.
A lot of auto parts stores will set their brake lathe to mill the rotor to the minimum thickness. The end result will be that you will not be able to turn those rotors again in the future.
Have them checked for warpage and thickness. If not warped, just clean them up and use them. The brake pads will get rid of the surface rust (assuming no pitting). But they need to be clean.
I’ve seen two types of proportioning valves. One has 1 line to the rear. This goes to the rear wheels. It then has 1 line out on each side, which is for each front wheel. It also has 2 inlet ports, one for each chamber in the master cylinder.
The other type has one less outlet port. That is to say that it relies on a second smaller valve that splits the single front line in two, one for each wheel. I suspect you have this one.
Inspect your balljoints and other front end parts for wear, and replace accordingly. Take a look at the rear brakes too.
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Content last modified: January 23, 2014 at 12:10 am