Mark L

After consulting with Jim Turner, we decided the new master cylinder might have been bad out of the box. The new one arrived on Friday Sept. 20. After bench bleeding it, I installed it, along with a good used booster I got from John D. I installed them Sept. 21 and re-bled the entire system. Same results, pedal goes to the floor with almost no resistance. Thinking I may have not adjusted those finicky Cadillac rear calipers the right way, today I did a complete simulated rear pad replacement and readjusted the parking brake levers so they have no more than 1/8th inch travel off the stops before the pads clamp on the rotors, and re-bled the rear lines. No good. The brake pedal still goes to the floor with the engine running. I've been through almost 4 quarts of brake fluid bleeding the system. All the connections are dry. Other than capping the front line, then capping the rear line to isolate the side where the problem is, I'm not sure what else to do.

Short story: After consulting with Jim Turner, we believe the new master cylinder is bad, out of the box. Today I had more time to work with the pushrod between the booster and the master cylinder. I initially shortened it, and the brakes were much worse when the engine was not running and running. With the engine not running, there was a lot of pedal travel before there was any resistance. With the engine running, the pedal went straight to the floor. I then returned the pushrod length back to its starting point, then began incrementally lengthening it one or two full turns each time. After each adjustment, with the engine not running, the brake pressure built up earlier and earlier ("higher" brake pedal) and was firm. With the engine running, the pedal still moved about 3 inches without any resistance before finally building up pressure towards the end of the stroke, getting firm about 1/2 to 1 inch above the carpet. Then, the pedal slowly sank to the floor as I held pressure on the pedal. The single MC on my Lark Daytona was like that before I replaced it. The pedal would initially be firm, then pressure slowly bled off due to an internal leak. Also, each time I lengthened the pushrod, I checked to see if I could turn the rotors at each wheel by hand when the brake was completely released. The longer the pushrod was, the harder it was to turn the rotors by hand. This meant the pushrod was too long (wasn't allowing the fluid pressure to release from the calipers). I spoke with Jim Turner. He had one last new MC on the shelf, so he's shipping it to me tomorrow. I should have it later this week.

Congratulations. That's a beautiful color combination. It appears to have been maintained well.

John, I checked my Lark chassis parts manual. If the '63 Cruiser the booster came from had disc brakes, it's the same part number as on the '63 Avanti.

Yes, I initially adjusted the eccentric to get the 7/8" measurement in the shop manual. Since the pedal is going to the floor, I've temporarily adjusted the eccentric to get the pedal as close to the seat as possible so I can get more pedal travel. I've spoken with Jim Turner for additional advice, and when the weather improves in a few days I will work with the pushrod adjustment some more, experimenting with various changes to see what happens. Other than adjusting the pushrod, I have not disturbed the booster. I still have my Lark manuals. I'll compare the part numbers and let you know if I can use it. Even if it's remporary, it looks like it would be an easy swap. Thanks.

After work today I bled the master cylinder again, on the car using the brake pedal to provide a full stroke and additional leverage over the internal springs. I think some additional air was bled out. Since I disturbed both brake lines coming off the MC, I re-bled the entire system. It appears there was additional air in the rear circuit. I then had my daughter hold pressure on the pedal while I slowly loosened the plug I installed on the junction block. I heard a tiny pffft, immediately followed by a dribble of brake fluid and my daughter saying the pedal was now slowly moving toward the floor. I then quickly tightened the plug while she kept pressure on the pedal. The brakes felt better afterward, but I wasn't able to start the car to really test it. I determined all my activity at the MC had disturbed the lead wires at the start solenoid. By the time I figured this out, it was getting dark and time for dinner. I'll test the brakes using the booster tomorrow after work.

I confirmed in the instructions provided with the MC by Jim that the rod is to be adjusted so there is only a small gap (0.005 or less) between the end of the rod and the cup on the piston when the mounting flange of the MC is against the face of the booster. Since the piston cup on the new MC was as not as deep in the piston as on the original MC, the rod had to be shortened vs. the measurement of 1.245 to 1.250 listed in the shop manual in order to get the MC to seat on the booster. It's very possible there is air trapped in the drilled passage between the plug and the center of the junction block. The block started out as a solid piece of brass. The areas drilled/tapped/machined for the flare nuts are at most only 5/8" deep into the sides of the block, but the block is about 2" across. That means there's about 3/8" length of a drilled passage that's only 1/8" to 3/16" in diameter before all the drilled passages come to a common point in the middle. If the passage is oriented with a vertical angle, there's space for an air bubble to be trying to rise up against the plug I installed. You have to remember, I replaced all the brake tubes, and I removed the junction block from the frame to clean it. There was absolutely no brake fluid anywhere in the system before I refilled it, only air. Any part that touched brake fluid was replaced, except for the junction block, and that was thoroughly purged.

I'll call Jim Turner tonight since I bought the MC from him. His instructions say to make sure it's adjusted properly, but doesn't give a value. I bench bled the MC, but thinking back, I may not have had enough arm strength to fully push the MC pistons against the internal springs and get a full stroke. Since the MC is now installed, I think I'll re-bleed the MC on the car, since the brake pedal and my leg will provide more leverage. Also, I was thinking about the plug I installed in the brass junction block where the line to the rear axle use to connect. The junction block is now oriented so that the plug is somewhat above the center of the block. There may be an air bubble trapped at the end of the plug that can't be flushed out. After I re-bleed the MC and the lines, I'll have an assistant push on the brake pedal while I loosen the plug to see if there is any air trapped in the junction block, then I'll re-bleed the front lines.

The 1.245 to 1.250 measurement is for the stock single MC. Before I installed the new MC, I measured the distance to the piston from the mounting face. The old stock MC matched the dimension in the shop manual, but the distance to the piston on the new Raybestos dual MC was much less. I shortened the pushrod to match the new MC. Otherwise, keeping the stock MC dimension with the new MC would cause the pushrod to compress the piston during installation. It's only suppose to have a small gap when installed.

Regarding the tool, the Avanti shop manual has a drawing that shows how to make a tool, but it would only work with the stock MC. I could make a custom tool that does the same thing but matches the dimensions of the new MC. Removimg the hose and plugging it while the engine is running would be just like shutting the engine off, letting the vacuum bleed down, then pumping the brake pedal until all the vacuum onside the booster is used up. I've already done that. The brakes work better in manual mode with the engine not running. I tried installing an O-ring instead of the gasket, but the O-ring I had was too thick. I couldn't get the valve to reinstall.

I just completed the following: New flanged rear axles Turner disc brake conversions, front and rear All new brake tubes All new flex hoses New dual master cylinder Eliminated the hydraulic stop light switch and installed a mechanical switch at the brake pedal. The port on the MC for the hydraulic switch is plugged and sealed. Today I filled the system with fresh DOT 4 fluid and bled the brakes. I found two leaks in the rear circuit. I tightened the leaky fittings and bled the rear brakes again. With the engine not running, the brakes feel firm as they are applied, and I can see the booster and master cylinder flexing upward slightly very soon after I start pressing the pedal and as resistance builds up in the pedal. This is the problem. The car is completely off the ground on jack stands and the wheels off. When I start the engine and apply the brakes, the pedal goes almost to the floor before I feel any solid resistance in the pedal. The booster and master cylinder do not flex up slightly until the pedal is nearly to the floor. As the pedal is nearing the floor, I can hear a change in tone in the engine as if there is an additional load on the engine. With the engine at idle and the transmission in drive, and no pressure on the brake pedal, the rear axle turns. If I apply the brakes, the rear axle does not stop turning until the pedal is nearly to the floor, which seems to indicate to me that the booster is not applying pressure to the MC until the pedal is near the floor. I removed the check valve on the booster and confirmed it only allows air to move towards the engine. I removed the vacuum hose between the check valve and fitting on the intake manifold and verified it is clear. With the check valve installed and twisted into position, it is still a little loose on the booster. There is one gasket in place. When I installed the MC, I had to shorten the length of the actuating pushrod. The contact point on the piston is at a more shallow depth than the original MC. I adjusted the rod so that the rod is not putting any pressure on the piston as the mounting flange seats on the face of the booster. Lengthing it by one or two flats of the nut changes how the MC seats on the booster, so I know it's adjusted right. What am I missing? What should I check next? I'm not going to drive it until I figure this out. It wasn't doing this before I did all this work. The front brake pads were worn out, but the car was stopping and the brake pedal resistance was better than this.

Dwight is correct, the spindles do not come in the kit. I also opted to buy the stainless braided flex lines. I think I figured out a way to reuse the original backing plates. It looks like I can possibly swap them side to side and trim them to match the new calipers. That will need to be a future project, however. I didn't come to this conclusion until after everything was assembled. I'll order the aviation grade bolts for the caliper brackets and do it all at the same time.

Today I finished installing the Turner front disc brake kit on my Avanti. The following is not necessarily described in the instructions that come with the kit. The original Dunlop/Bendix calipers mount to the forward (bumper) side of the spindle. The Turner kit installs on the rear (firewall) side of the spindle. Yes, the new bearing spacers supplied with the kit need to be really hot before they will fully seat on the spindles. The instructions say it should be red hot. It is only a 0.002" interference, so I didn't think it needed to be red hot. I was wrong. This is what did not and what did work: The instructions say to use a torch to heat the spacers so they expand, but I was concerned I would not be able to heat them evenly from ambient temperature. I borrowed one of my wife's cast iron fry pans (WITH permission, of course). I pre-heated the oven to 450F, and baked the spacers in the pan for about 20 minutes. Using a very thick oven mitt, I then quickly carried the pan outside to the car, where I had everything ready to quickly install the spacer. I used channel-lock pliers to pick the spacer out of the pan. When I installed the first spacer, it got to about 1/8" from fully seating and got stuck. Once it touched the spindle, the heat from the spacer immediately started to transfer to the cool spindle, causing the spacer to contract and the spindle to expand. I tried to re-heat the spacer with a torch, but the spindle was also getting very hot (along with the kingpin). I ended up sliding the box end of a 1 1/4" wrench over the spindle, seated the box end against the spacer, and used a hammer and long drift punch to drive the spacer on the last 1/8". I nicked the spindle several times. I had to file down the nicks so that the inside rotor bearing would slide on the spindle. What worked for the other spacer: I heated the oven to 500F and baked the spacer again for about 20 minutes. When I took it outside, I left it in the pan, then used a propane torch to heat it in the pan even more. The pan was so hot that a pot-holder I had placed under the pan to keep from burning the driveway was scorched brown. the spacer turned blue all over, then the blue color faded. I then used the channel-locks to put it on the spindle. This time, it was loose on the spindle and slid all the way on. I used the channel-locks to keep it pressed tight against the face of the spindle until it cooled and clamped onto the spindle shaft. Personally, I feel having a pressed-fit spacer is overkill. I almost botched the installation the first time, and once it's on the spindle, it's permanent. The mounting brackets for the calipers are not marked left or right. The bracket plates appear to be identical. The wide end of the bracket is at the bottom. The brackets mount to the engine side of the spindle, to the firewall side of the kingpin. There is one spacer that installs on the shank of each bolt for the brackets. They go between the bracket and the engine side of the spindle. The shoulder end of each spacer fits inside the spot-face on the engine side of the spindle. When the original caliper and backing plate are removed, the outside and engine side faces of the spindle and the three holes on the firewall side of the spindle need to be cleaned, including the spot-faces on the engine side of the spindle that surround each hole. The spot-face areas are not deep, but a mirror and light may be necessary to see that the entire spot-face area is clean. The original backing plate is not re-installed, ande a new backing plate is not supplied with the kit. I find this concerning, because the kingpin is about an inch away from the engine side face of the rotor once the rotor is installed. When the suspension and kingpin bearings are lubricated, care will need to be taken to ensure no grease gets on the rotors, or else there will be a loss in braking effectiveness. The original backing plates had a lot of excess grease sprayed on them over the years, so it will be really important to thoroughly remove any excess grease after lubricating the suspension. Any grease that does get on the rotors will need to be removed with brake cleaner. There are 6 total bolts that attach the brackets to the spindles, three for each side. Each bolt supplied with the kit is 2 inches long. When I got them installed, the tips of the bolts were flush with the ends of the nuts. This means that when you torque the nuts, the very last thread to the tip of the bolt is under a load. This may cause the threads on the bolts and/or nuts to strip. In aviation, the rule of thumb is that one to three bolt threads must protrude beyond the end of the nut when the nut is fully torqued. The problem is, longer automotive bolts usually only are available in half inch increments. The next automotive bolt length available is 2.5", which is too long. Aviation bolts, however, are available in 1/16 increments. The next time I need to remove the rotors, which also requires the calipers to be removed, I am going to replace the 2" grade 8 bolts supplied in the kit with aviation grade bolts that are 2 1/16" or 2 1/8" long. Aircraft Spruce and Specialty Co. ( www.aircraftspruce.com ) sells aviation bolts. When I installed the calipers, the caliper was binding slightly on the sides of the spacers. This prevented one of the bolts that secures the caliper to the bracket from aligning with the threaded hole in the caliper. I used a hammer to gently persuade the caliper that it was in its best interest to shift a little to get all the holes to align. Overall, everything seems to fit well. Tomorrow I will fill and bleed the system to see how it all works.

I was finally able to finish my master cylinder installation and the last of the new brake tubes. I started installing the front disc brake kit. I'll post some tips on that later tonight or tomorrow when I have more time. I think I'm on the downhill side of the installation. I probably won't have time to bleed the system and test it tonight. I took the day off from work tomorrow, so I should be able to road test everything then.

My apologies for the confusion. I double-checked today, and mine are installed just like in wildfelr's photograph. I don't know how I missed that.

Yes, the photograph helps. I double-checked today, and mine are installed like yours.

Yes, the shortest leaf is against the axle pad. I guess it sits lower. This is the first Avanti I've owned, so without having a correct Avanti sitting next to it, I have nothing to compare with it. It's currently on jack stands, so I can't do any accurate measurements at the bumper, etc. I'll post some photographs later.

While I've been working to install the disc brake conversion on my rear axle, I've been looking around at other things to get more familiar with the car. One thing I noticed is that both rear leaf springs are currently oriented like a rainbow, with the ends lower than than the middle where they are bolted to the bottom of the axle. The long leaf with the bushings on the ends is on the bottom, and the smaller leaves are on the top, between the long leaf and the axle. It doesn't match the orientation in the parts manual. I think mine are installed upside down. My impression is that either someone did not know the correct orientation when they were installed, or someone intentionally flipped them over to lower the rear of the car. I'm going to fix them, but will there be any long-term problems driving on them like this until I can get them right side up?

That's why I sprung for Jim Turner's deluxe kits, because they included everything. Other than having to identify the interchange numbers for the rotors so I could buy the correct drilled/slotted rotors, there was no work on my part assembling the parts.

I bought my master cylinder from Jim Turner. I bought my brake lines from Inline Tube. I haven't installed them yet. I bought the drilled/slotted rotors from Brakeperformance.com. Jim Turner only provided plain/smooth rotors in the deluxe kits. He doesn't sell drilled and/or slotted rotors. I'm still working with the rear brakes, primarily trying to get the emergency brake sorted out. Jim's instructions indicate the stock rear cable will be too long and needs to be shortened. I measured it and shortened it, but when I reinstalled it, I found that I didn't need to shorten it at all. I'm now waiting on a replacement cable to be shipped.

I'm right in the middle of doing a 4-wheel Turner disc brake conversion. While I'm at it, I'm installing a new dual master cylinder, new brake lines, new brake hoses, and installing flanged rear axles shafts from Myers Studebaker. I'll probably also install a mechanical brake light switch while I'm at it. I'm doing this on evenings and weekends, so I hope to be done by this coming Labor Day (US) weekend. When I'm done, I plan to sell all of the removed parts, plus sell the new, plain rotors that came with the deluxe kits. I upgraded to drilled and slotted rotors.

Indianapolis 500 winner Rodger Ward's Avanti R1 is now up for auction on Bring A Trailer. This is the one he requested instead of the R2 that Studebaker originally planned to give the winner of the Indianapolis 500. https://bringatrailer.com/listing/1963-studebaker-avanti-61/ If owning just any 1963 Avanti is not enough, this one is even more special.

They're still being advertised as of August 10, 2024: https://portland.craigslist.org/yam/cto/d/yamhill-1963-studebaker-avanti-projects/7769668273.html

Plus, they had a 4-cylinder engine in development in the early 1960s. If a decision had been made to put it in production, that might have also helped the company when the gas prices shot up.

Is that a Jaguar or a Corvette in front of the Avanti?