1958 Cadillac Sedan Brakes

[Guest mrclean1]

Now that my car is road worthy and I've put about 150 miles on her, never having driven her before I'm not sure what to expect. The car has a rebuilt booster and master from Kanter, new stainless brakelines, new rubber lines, new wheel cylinders, drums have been turned, system filled with DOT 5 fluid and all new shoes installed.

At slower speeds everything works fine, light pedal pressure brings us to a steady stop with no pulling or noise. At moderate speeds, braking begins normally then the pedal gets very hard and requires a huge amount of pressure almost as if it loses its power assist. I'm guessing I have a booster or vacuum issue, but having nothing to compare to don't know where to go with it. Finally, when shutting down, with my foot on the brake, shifting into park and turning the car off I hear a slight hiss and the brake pedal pushs back against my foot pressure, is that normal?

Any and all input is greatly appreciated, Thanks, Steve

[Rusty_OToole]

There is supposed to be a 1 way valve on the vacuum system, either on the engine or on the booster or even in the hose. Check if it is holding pressure.

Could also be a leak in the hose or booster.

[Guest Jim_Edwards]

Now that my car is road worthy and I've put about 150 miles on her, never having driven her before I'm not sure what to expect. The car has a rebuilt booster and master from Kanter, new stainless brakelines, new rubber lines, new wheel cylinders, drums have been turned, system filled with DOT 5 fluid and all new shoes installed.

At slower speeds everything works fine, light pedal pressure brings us to a steady stop with no pulling or noise. At moderate speeds, braking begins normally then the pedal gets very hard and requires a huge amount of pressure almost as if it loses its power assist. I'm guessing I have a booster or vacuum issue, but having nothing to compare to don't know where to go with it. Finally, when shutting down, with my foot on the brake, shifting into park and turning the car off I hear a slight hiss and the brake pedal pushs back against my foot pressure, is that normal?

Any and all input is greatly appreciated, Thanks, Steve

If you are hearing a hiss inside the car that appears to be from below the dash more than likely it is a booster seal issue where the rod goes through the firewall. Dorman makes a repair kit for the booster, but you'll need to know if the booster is a Bendix or a Moraine unit. Either of the kits are less than $10.00. While you've got the booster off, you probably should go ahead and rebuild the master cylinder. The master cylinder kit are made by Raybestos and the price of the kit for a Bendix kit is under $15.00 and the kit for the Moraine is around $11.00. Your local parts store should be able to get them overnight from their supplier warehouse for you or you can get them online from Rockauto.com

Jim

[Guest mrclean1]

Update..

I vacuum tested the booster. First, testing the check valve which does hold vacuum, then testing the tank which also holds vacuum. When the booster is plumbed in, no vacuum. So I contacted Kanter who sold me the rebuilt unit over a year ago and they told me to send it back for repair or replacement. So the problem is on the way to being solved.

[mrspeedyt]

went to your website... good job! '58 cads are the best looking '58s of any brand! keep at it... you'll get it sorted out.

Edited October 30, 2010 by mrspeedyt (see edit history)

[Guest Jim_Edwards]

went to your website... good job! '58 cads are the best looking '58s of any brand! keep at it... you'll get it sorted out.

It's a really great looking car, but there are some that might disagree that the '58 Cad was the best appearing of all '58s. It's all in the eye of the beholder.

Back in their day both '57 and '58 Caddy's were widely criticized for the hood length being greatly disproportionate to the trunk length giving them a bit of an unbalanced appearance. Having a '57 Eldorado Seville, I have to agree with those original assessments. Love the car, but have to admit the hoods are too short for the rest of the car. What was Harley thinking?

[Guest Jim_Edwards]

Update..

I vacuum tested the booster. First, testing the check valve which does hold vacuum, then testing the tank which also holds vacuum. When the booster is plumbed in, no vacuum. So I contacted Kanter who sold me the rebuilt unit over a year ago and they told me to send it back for repair or replacement. So the problem is on the way to being solved.

Was reading your article on the Adirondack Nationals on your web site and your comments regarding the "Vinyl Roof" on a '57 caddy Eldorado Seville. The '56 Eldorado Sevilles were the first to sport a factory "Vinyl Roof." However, they weren't really Vinyl they were of the same material used for convertible tops of the time. If the car at the Nationals had a Vinyl Roof it was a replacement and likely as close as one could get pattern wise to the convertible top material in use at the time of original production.

It's fun trying to get a handle on all the codes on '56 and even '57 Eldorado Seville ID plates as some of them were apparently never properly documented for posterity. The "Vinyl Roof" on '56 models being among those codes. Unfortunately few people associated with Caddy production in those days are still living and even at that may not have been involved with all aspects of the car. Lot's of undocumented production engineering changes, particularly with the '56 models. There's a couple of codes on my '56 that not even the year expert of seven years ago with the Cadillac/LaSalle Club had any knowlege of and he was a young Cadillac Division production engineer at the time the car was produced.

[mrspeedyt]

I was thinking... my '62 cad is having a bit of a idle issue... I have to left foot brake and play with the throttle a bit to keep it running and noticed that above a idle speed that it takes more effort on the brake ... guess less vacuum is available... and as far as '58 style... weren't all the cars kinda short on the hood length.... but certainly the cad was really long in the back... it was the 'look'!!

[Guest Jim_Edwards]

I was thinking... my '62 cad is having a bit of a idle issue... I have to left foot brake and play with the throttle a bit to keep it running and noticed that above a idle speed that it takes more effort on the brake ... guess less vacuum is available... and as far as '58 style... weren't all the cars kinda short on the hood length.... but certainly the cad was really long in the back... it was the 'look'!!

I wouldn't put that Caddy on the street until you figure out what is causing the problem. Could be anyone of the common three issues, i.e.; Fuel delivery related, timing issues, or as you suggest vacuum leak. I'd check everything in the fuel delivery system before going nuts. Fix could even be as simple as a fresh air filter or fuel filter, but I'd be more inclined to think a carburetor rebuild is in order.

Everyone in the time criticized the GM hood lengths but the real problem was it resulted in the engine compartments being more than a bit short of space. I think GM's design department had more of a problem with undersized engine compartments in the late 1950s and early 1960s than the others. Engines must have been viewed as a necessary evil it would seem. On the other hand they unquestionably had the largest trunks, which meant one didn't have rent a storage unit for all their junk........

In my mind in the same period of time GM had the most attractive interiors of all the auto makers. Even their low end products had very decent interiors.

[Guest mrclean1]

@ Mrspeed..

Sounds exactly like or very close to what I am going through. Bad idle when in gear, but very smooth when in neutral. Occasional stalling in gear, have had to use left foot brake routine too! Can't get the timing right and have her run well, have to time her by ear, this on a newly re-built motor (less than 300 miles) and re-built carb.

Can't give you the solution yet, but vacuum testing points right at the booster and it's going back to Kanter this week, once it's back we will know for sure. Be careful with those brakes, that's a pretty heavy car to try and do a "Fred Flintstone" stop

Steve

[mrspeedyt]

ain't that the truth... on my '63 cad the front brake portion of the master cylinder suddenly failed and it required LOTS :eek: of foot pressure to stop the car with just the rear brakes.

[buick man]

Have you recurved the distributor to accommodate the new ##### fuels?

Have you enlarged the AFB idle channel restrictor to cure lean-off idle stumble assuming you have the Carter AFB 4-bbl due to the ##### present day reformulated fuels?

Have you reset your timing as per your new re-curved distributor advance?

Just a few I can think of - Off the top of my gray mater.

"Maybe they forgot to turn off the sausage machine on the 58 Caddy so by the time it got to the end of the car it was just a little elongated."

Edited November 3, 2010 by buick man (see edit history)

[Guest mrclean1]

Booster Update...

Pulled it out Nov. 1 and sent it back to Kanter. Jim called me Thurs. to say it definately had a fault and that they would take it apart, get the parts needed and get it back to me end of next week. Hopefully this is going to solve many of my issues.

[W_Higgins]

While it's gone, have you tried just capping all your vacuum ports and running it to help narrow things down?

[Guest mrclean1]

@ W Higgins

Not Yet, but hoping to get the time to run it awhile tomorrow. Though she starts, idles and runs like a dream in the garage. My problems crop up under load on the road.

[W_Higgins]

You mention having done a lot of other stuff, but did you rebuild the distributor while you were doing the rest of the work? Vacuum problems don't usually show up at higher speeds unless they are massive.

[Guest mrclean1]

@ W Higgins,

I did go through the dist. Replaced the points with a Pertronix unit and replaced the vacuum advance with a new one to the same specs. Need to test that advance and be sure it is not advancing to soon. The centrifigal advance is free and seems proper. I still think it is a carb issue but can't persue that until the booster is back.

The car starts, fast idles and then idles great when warm. No stalling issues, pings, knocks, etc. When on a flat straightaway, hard acceleration will kick down the tranny and go up smooth, however, when accelerating out of a turn or up a curving highway ramp she will hesitate and buck as if starving for fuel. I suspect a float level issue, carb rebuilder says no way. I will re-adjust the carb when the booster is back, because we apparently were adjusted to compensate for that huge vacuum leak at the booster. If a road test then still shows problems, the car will go to the carb shop as a running vehicle instead of just a carb on the bench. Don't know what else to do with it..

Thanks for your advice....

[W_Higgins]

I was thinking possibly floating points or walking distributor cam from the bushings being work out, but that scratches that.

Tell me this -- this late, do Cadillac carbs still use the sight plug in the side of the bowl to check fuel level? I recently had a very similar problem with a '42 Cadillac where somebody else had built the carb. Took it apart a couple of times, measured the float level, etc. and everything was spot on. Checked through the plug hole and it was way low. This time I ignored the float measurement and just kept bending it up until I got the fuel to the hole and perfecto. Guy that built the carb is a Cadillac guru and we're still not sure where the off-measurement comes from, like if it's a slightly different float from another model, maybe the needle is a little long, or what. The float is so high now when it's closed that it nearly touches the inside of the top. Someday we'll dissect it against his known correct '47 carb that should be the same.

Even with the booster leaking, it would have to be a big honking leak to cause a problem like that when cruising down the road. It could also be a combination of both on a more minor level.

[Guest mrclean1]

No, there is no sight plug, it is a Rochester 4GC. As far as the vacuum leak, it was like just having the vacuum port open, because it could not pressurize the system and shut down it just kept sucking air as long as the motor was running.

I'll just have to wait another week or so to see what is going to happen.

Steve

[Guest mrclean1]

Is it possible my fuel pressure is to low? Have not checked that and it is a new fuel pump?

[W_Higgins]

Is it possible my fuel pressure is to low? Have not checked that and it is a new fuel pump?

More likely that low fuel flow could cause a low fuel level type problem at higher speeds. Not so likely with a new pump. You don't even need it running to check that. Just disconnect the line and let it pump into a cup. Should shoot a heavy slug each time even just at cranking speed.