Q: Upgrading to Disc Brakes on 1968
One of the first things that I would like to do to the 1968 is improve the braking system for SAFETY of my family. Do you recommend disc all the way around? This car has no power brakes right now and drums all around.
What components from which cars will I need to start collecting now so that I have the parts when I go to do it? Can you compile a shopping list for me?
A: Do you want the correct-for-68 4 piston disc brakes, or the 1969 style single piston set-up? The 4-wheel discs are nice, but not necessary, and maybe more work than necessary to achieve what you are looking for. Your best bet (barring the correct 4-piston system) is the 1969 F-body style and you can get with the guys who offer a complete set-up with some new parts, for a very easy change-over. If you can do your own brakes, get the master cylinder, booster, and related valves attached to it all from a 1969 bird or camaro.
If possible, get the spindles with the disc brakes atatched from the same car, or from a 69-72 A-body, it has the parts you’ll need. A-body cars are Chevelle, Skylark, Grand Sport, LeMans, Tempest, GTO, Cutlass, F-85, 442. The 69-72 spindles are the same, but the steering arm is different. However, the steering arm unbolts, and the Firebird one bolts on in its place. The spindles are a little different from drum to disc, but the same from F to A body.
On the list in the past week, it has been mentioned that some 1969 birds had a valve along side the left frame rail under the drivers seat, in the line to the rear brakes. This was for proportioning the system in cars that had V8 and AC, reducing the rear braking slightly.
Just so you know, the 1969 and 70 GM disc cars had separate valves for metering, proportioning and differential (the warning light switch). In 71 and later, GM went to a combination valve, incorporating all these things in one unit, usually found a couple feet below the master/booster assembly, mounted on the frame rail corner.
Still a few donors left out there. 69-72Grand Prix, Pre74 Nova, Apollo, Omega, Ventura ,70-72Monte Carlo, 68-72 A Body GM(Skylark, Chevelle, Cutlass, Lemans. Just try to get entire system; spindles, brake line, bracket, master cylinder & booster with proportioning valve.
I’ll share my experience with all of you, since there might be some useful bits here.
My car originally came with drum brakes, and had been sitting in a San Francisco carport for about 5 years. The brakes were in pretty bad shape. When I tore the car down for restification, I decided that I wanted to upgrade to front discs. At about the same time, I found an ad locally for the following 1969 Firebird parts:
Used Calipers & Flex hoses
Spindles & Caliper brackets
Upper & Lower Control Arms
I used the calipers as cores and bought rebuilt units, without pads. The 2 piece rotors were revealed to be too thin to reuse. But I had a set of new 1 piece rotors for an El Camino that turned out to be a direct replacement. I then bought new braided stainless steel hoses, Performance Friction carbon metallic pads (only $24!), a complete set of stainless repro hard lines, new bearings, and new rear brake hardware as well as shoes.
The control arms had new lower ball joints, but one had damaged threads on the spindle stud, so I replaced that. They both had new rubber bushings, but the upper arms needed new bushings as well as ball joints. I had all of the used parts beadblasted, and then had a machine shop install the one lower ball joint as well as the upper arm bushings. Once that was done, I painted everything with POR-15. I also cut 1 coil off the front springs, blasted and painted them. The car sat a bit high up front by my tastes. Once assembled, the height was just what I wanted.
Other parts I got were a rebuilt master cylinder, along with a rebuilt booster. The rebuilder offered to plate the booster in silver cad, versus gold cad which most restoration parts suppiers use. Silver cad is actually the correct plating used by Pontiac, and while I wasn’t doing a restoration, I liked that detail. The old drum brake master/booster was acceptable as a core. I had a new proportioning valve from Master Power Brakes that I’d bought for another car, but didn’t use.
Upon assembly, most things went on pretty easily. The problem areas might be of interest to some.
-Rear Axle hardlines needed minor rebending to fit the 2nd gen. housing I was using. The 8.5″ has a different location for the flex line mouning as well. Not a big issue.
-The front to rear line had a different sized fitting compared to the port on the rear of the prop. valve. I was able to find a correctly flaired adapter to make the two fit. The bends in the line were in all the right places and fit very well otherwise.
-The 1969 flex line brackets were not a direct bolt on to my 1968 subframe, and figuring out the best mounting location was difficult. I didn’t have a 1969 disc brake car to use as a reference, so I guestimated the ideal location. Getting the hardlines to cooperate with these locations was a bit difficult. Stainless lines are quite a bit harder than the mild steel originals, and are a but tougher to bend. Even harder to flair if you use bulk line to create your own.
-Driver side fitting didn’t match the appropriate port on the prop valve. There wasn’t an adapter to be found that had the right sided flair, and so I had to get a line made up at a local shop that made up hoses and lines for industrial equip- ment.
Each of these problems were time consuming to resolve, and were a source of occasional frustration. I can see where buying a complete conversion kit from someone like Master Power Brakes, Classic Industries, or one of the many other sources would probably result in less fabrication, and take less time to install. I was on a very tight time sched- ule, and could ill-afford the time lost. I was trying to get the car ready for Hot August Nights ’99 in Reno, Nev.
I got all of the problems resolved, but wondered if I would have been better off buying a kit. Costwise, I came in just about $195. more than the kit. But I got some better parts as a result.
|(turned out to be unusable)
|(turned out to be unusable)
|(used as cores)
|(upper and lower)
|Hoses and brackets
|(dumped the hoses, used the brackets)
|Calipers x2 (Bendix rebuilds)
|Beadblasting various parts
|Rebuilt Master and Booster(incl. plating)
|Stainless Brake lines,front,rear,axle
|Braided stainless flex lines(front and rear)
|Front Brake Pads (Performance Friction)
|Front Wheel Bearings and Seals
|Fabricate New LH Hardline
|Misc. flaired nut adapters
|1 Piece Front Rotors (Bendix)
|Proportioning Valve (Master Power)
Not included are brake fluid, rear shoes, rear brake hardware, rear axle seals, upper control arm bushings, and new front end parts like ball joints, idler arm, inner and outer tierods, rear springs and related hardware. All of which were replaced, but not related to the disc brake conversion.
Firebird Specialties sells a front disc brake kit, with all new components, for $795. I don’t know if the hardlines are mild steel or stainless. I assume they are mild. Some of these kits have a cad. plated booster, others have a painted booster. All feature regular rubber flexlines. They also sell a kit w/used parts for $350. But research would be needed to determine what would need to be replaced or repaired in that kit.
Overall, I’m very happy with the performance of the brakes. Stopping is excellent, with no drama what- soever. The PF pads don’t squeak, and don’t seem inadaquate when cold. It was a bear resolving some of the compatibility issues, but the results make it worthwhile.
A: In corrisponding with another list member, it has come to my attention that I should have been a bit more clear on in the disk brake story that I related. The minor question he had led me to think about some of the other things I wrote about.
-It wasn’t necessary to change the control arms when upgrading to disk brakes. I got the spare set of arms as bonus material with the brake conversion parts. Having extra arms allowed me to prepare them and still have the car able to roll around. Also, while I was getting these parts ready, the car was in the body shop, so being mobile was especially useful. And since I was on a short schedule, any place where I could multi-task was helpful. But the control arms are OK for either brake system.
-Actual cost. Ever read a magazine article where some guy boasts that he’s got only $3500 in a car, but has replaced the engine, trans, interior, and repainted the car? Seem bogus to you too? I listed all of the costs, even for those parts I aleady had. That way you know the whole story. Kind of like the new slant that the magazine Car Craft has taken lately. They list all of the hassles they run into, and even list little items like the cost of bearing grease and zip ties. I didn’t get that detailed, and there were plenty of trips to hardware stores for stainless steel fasteners, clips, and whatnot that didn’t get into the cost. But you did get a fairly good representation of what it took to get the car converted.
-Brake lines. I got rid of all of the old lines, yet described the car as having sat for only 5 years. When I opened the master cylinder up, and also when I opened one of the brake lines, what poured out was dark like coffee, and had lots of rust flakes floating in it. A clear indication that the brake system was rusting on the inside. Many of the flaired nuts at various joints were either rusted or had the corners rounded off. My feeling was that the car probably sat for even longer with previous owners, and I didn’t want to build my brakes on a shakey (or rusty) foundation.
-Extra upgrades. I admit to being a bit excessive when it comes to nearly anything automotive, but especially brakes. I could have save some money on brake hoses rather than use the braided steel units. And I probably really didn’t need the carbon metallic brake pads, or stainless steel lines. But, since I was replacing all that stuff, I wanted it done the best way possible, within the limits of my budget.
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Content last modified: January 26, 2014 at 3:51 pm