1956 Thunderbird power brake problem

[jakesbackyard]

I recently purchased a 1956 Thunderbird that had a frame off restoration finished in 1995. It only had 15k miles since restoration and had been kept in a climate controlled place. I have gone through pretty much the whole car doing maintenance to get to good driving capability. I’m having difficulty with the power brake system. It had a disc front kit upgrade with dual master cylinder and upgrade rear drum cylinders. It doesn’t seem to have any power assist. All four wheels lock up with hard pressure, but there is no lowering of the pedal when starting car. It takes hard pressure on a hard pedal for stopping. It is plumbed correctly according to a diagram I found which has the power only to the front discs. The power system will hold a vacuum overnight. It has a regular brake light switch and no proportion valve.

Does anyone have ideas on what could be wrong? Or what to check. Thank you.

[oldbugger]

Welcome to my world, I have a 64 and it has the same issues Hopefully we can both learn a lot, thanks for posting

[miker98038]

Those old systems are different. The remote booster is probably a Midland, and with a disc conversion only boosts pressure to the front disc. That’s it, it’s how they worked.

There’s no easy way to put a modern booster on an early bird. The hood latches don’t clear. Move the battery to the trunk and the brake pedal over where the clutch would be. Not much help on a manual transmission.

I’m using a hydroboost off the power steering. It’s way light, I wouldn’t recommend it. But I ran a set up probably like yours for years. It’s just how it is.

No idea on a 64. Different style booster, but here’s a link for that

Here’s a link on that question. Read down a bit.


https://forums.fordthunderbirdforum....ter-woes.9893/

https://forums.fordthunderbirdforum....booster.14855/

[jakesbackyard]

Originally Posted by miker98038

Those old systems are different. The remote booster is probably a Midland, and with a disc conversion only boosts pressure to the front disc. That’s it, it’s how they worked.

There’s no easy way to put a modern booster on an early bird. The hood latches don’t clear. Move the battery to the trunk and the brake pedal over where the clutch would be. Not much help on a manual transmission.

I’m using a hydroboost off the power steering. It’s way light, I wouldn’t recommend it. But I ran a set up probably like yours for years. It’s just how it is.

No idea on a 64. Different style booster, but here’s a link for that

Here’s a link on that question. Read down a bit.


https://forums.fordthunderbirdforum....ter-woes.9893/

https://forums.fordthunderbirdforum....booster.14855/

Thanks for the info and first link. It is a midland and has silicone fluid that I assume has been in since converting to disc. The fluid is purple and very clean in the MC. I’ll make sure that vacuum is sufficient and see if I can hear the diaphragm moving. Should the pedal still drop a little when starting if it’s working? Thanks for any more info. Here’s a photo of the unit.

[cos]

Hello If you are a member of CTCI club might research it there. Lots of info on early birds. That may be where Miker referred you to.

[miker98038]

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Find a hill with no one around. Slow the car to 15 mph or so, put it in neutral and shut the engine off. Pump the brakes to use up the vacuum in the booster. Then with the brakes on and the car rolling restart the engine. You’ll feel the boost come in. On my hydro unit it puts you thru the windshield. On the Midland, not so bad.

I learned this by accident pushing the manual choke in too early and leaving my neighborhood down a long hill. Obviously you need to be out there alone, no traffic.

Good call on CTCI, my links just came up at random.

[jakesbackyard]

Originally Posted by miker98038

Find a hill with no one around. Slow the car to 15 mph or so, put it in neutral and shut the engine off. Pump the brakes to use up the vacuum in the booster. Then with the brakes on and the car rolling restart the engine. You’ll feel the boost come in. On my hydro unit it puts you thru the windshield. On the Midland, not so bad.

I learned this by accident pushing the manual choke in too early and leaving my neighborhood down a long hill. Obviously you need to be out there alone, no traffic.

Good call on CTCI, my links just came up at random.

Thanks for the info. Seriously hard to find a hill in the plains of ND. lol.

I’m really interested hearing from someone with a similar set up as me to know how the system reacts when working.

[miker98038]

I missed your location. My wife was from Glen Ulin, west of Bismarck. Try coasting down from 60 or so. If you ever drive that slow,

When I had the front disc, Midland, rear drum combo from a major tbird supplier it never felt like a power booster. Not like the big firewall mounted ones.

The one thing I remember is you had to have the rear brakes properly adjusted, or the pedal travel and stopping was terrible. When 1 click on the handbrake helped the braking it was time to crawl under and adjust them.

[jakesbackyard]

Originally Posted by miker98038

I missed your location. My wife was from Glen Ulin, west of Bismarck. Try coasting down from 60 or so. If you ever drive that slow,

When I had the front disc, Midland, rear drum combo from a major tbird supplier it never felt like a power booster. Not like the big firewall mounted ones.

The one thing I remember is you had to have the rear brakes properly adjusted, or the pedal travel and stopping was terrible. When 1 click on the handbrake helped the braking it was time to crawl under and adjust them.

lol. I live in the Red River valley (really flat). Interesting you mention the hand brake. When I got the car it didn’t do much. All new everything in the drums. So I adjusted them to work great. After about 100 miles they don’t do much. Not sure what the story is there. I’ll continue to mess with the power and see what I come up with. I do all my own work. Have built quite a few cars. Was just hoping someone had some good info on these.

[miker98038]

They used to “arc” the shoes to fit the drums. Pretty hard to find anyone who still has that equipped today. But if they aren’t done then your initial adjustment is a small point of contact. It’ll wear off in 100 miles, so it needs another adjustment. It gets more complicated when you turn the drums, etc. But you might ask around, where you are people are less inclined to throw things away. If I’m telling so something you already know, my apologies.

I’d tighten them back up, see what happens. There’s a link here somewhere on the parts to buy to retrofit 57 self adjusters to the rear drums. That really helps.

[jakesbackyard]

Originally Posted by miker98038

They used to “arc” the shoes to fit the drums. Pretty hard to find anyone who still has that equipped today. But if they aren’t done then your initial adjustment is a small point of contact. It’ll wear off in 100 miles, so it needs another adjustment. It gets more complicated when you turn the drums, etc. But you might ask around, where you are people are less inclined to throw things away. If I’m telling so something you already know, my apologies.

I’d tighten them back up, see what happens. There’s a link here somewhere on the parts to buy to retrofit 57 self adjusters to the rear drums. That really helps.

Thanks for the info. Even at 76 I learn something every day. Keeps a guy going.

[miker98038]

Well, I’m 76 also, and I’ve had this bird for 27 years. Most of what I learn seems to come from doing it wrong the first 2 or 3 times. Just trying to save others from my slow learning curve.

[RossL]

I installed disc brakes hoping that would solve the amount of leg pressure needed to stop the car. The discs did not solve the problem they need more pressure than drums. I upgraded my brake booster to a C490. It has a larger vacuum can and the piston is smaller with a longer throw resulting in more pressure.


The C490 was used on trucks (Dodge?), it's very rare and I paid $1,000 for it on eBay.


Expensive but now when I am coming to a stop, I don't have to press the pedal as hard. It works VERY well. Doesn't feel like a modern disc brake but I feel it was worth the cost.


I had to move the battery back an inch or two. Hood clearance using the original bracket was fine

[miker98038]

“Rare and expensive”. Maybe so, but the best solution I’ve heard in all the years of living with and reading these complaints. And probably better and cheaper than the hydro boost I ended up with. Nice job.

[Gene F]

FYI, the rule of thumb when installing a power brake system (most cars) is that the booster requires at least 16 " of vacuum on a warm engine at idle in gear.

Cars in general:
*a soft pedal squishy, or goes to floor is a bad master cylinder
*a hard pedal is a bad booster

Was this car equipped with power brakes when it left the factory?

[Gene F]

jakesbackyard, where did you find this car? 35 years ago baby birds were reasonably priced. Then they went outta sight price wise. Now they are moderating in price A LOT ! I like the 55s the best. I got a shirt for Christmas and it says "just one more car - I promise" Yeah right! LOL

[Bill's Auto Works]

I am following along as my Wife's Christmas Present was a 57 that someone converted the front to disc & while driving on Christmas morning she stated that she would have to work out a bit more as she was having some issues with pushing the pedal down. Unfortunately she had spine surgery due to stage 4 breast cancer that had metastasized to her spine, so she has to work even harder than most to push the pedal!

God Bless
Bill
https://www.jalopyjournal.com/forum/...closed.614419/

[dmsfrr]

Originally Posted by cos

Hello If you are a member of CTCI club might research it there. Lots of info on early birds. That may be where Miker referred you to.

jakesbackyard, here a couple links from CTCI about front disc brakes.
Unfortunately they haven't been updated in about 10 years so some of the info and sources for parts may no longer apply.

https://www.ctci.org/gilsgarage/disc-brake-conversion/

https://www.ctci.org/gilsgarage/disc-brake-performance/

Here are three more links.
Casco, Hills and Prestige all specialize in '55/'57 T-Birds with replacement, used original, new reproduction parts and in-house restorations.
Also free phone Tech Support.

https://www.classictbird.com/

https://hillsresto.com/

https://prestigethunderbird.com/

.

[jakesbackyard]

Originally Posted by Gene F

jakesbackyard, where did you find this car? 35 years ago baby birds were reasonably priced. Then they went outta sight price wise. Now they are moderating in price A LOT ! I like the 55s the best. I got a shirt for Christmas and it says "just one more car - I promise" Yeah right! LOL

This car was a consignment at GR Auto in Michigan. I had sold a custom 49 Ford I had built from scratch and driven for a few years. At 76 I didn’t want to build another car. I wanted a mostly done car to just personalize. Had always wanted a Baby Bird…preferably a 56. This one was the correct everything that I wanted, except I didn’t want the spare and a few other things. I’m pretty much a hot rodder at heart so I wanted to “personalize” it to me yet keep all the goodies for someone down the line to return it to stock if they like. And that I did.

Here’s a link to what I brought home… https://www.grautogallery.com/vehicl...rd-thunderbird

And here’s what it looks like when I took it for its first cruise about a month ago. I know some will cringe at what I did, but it can be put back in about 4 hours.

[jakesbackyard]

Originally Posted by dmsfrr

jakesbackyard, here a couple links from CTCI about front disc brakes.
Unfortunately they haven't been updated in about 10 years so some of the info and sources for parts may no longer apply.

https://www.ctci.org/gilsgarage/disc-brake-conversion/

https://www.ctci.org/gilsgarage/disc-brake-performance/

Here are three more links.
Casco, Hills and Prestige all specialize in '55/'57 T-Birds with replacement, used original, new reproduction parts and in-house restorations.
Also free phone Tech Support.

https://www.classictbird.com/

https://hillsresto.com/

https://prestigethunderbird.com/

.

Do I have to be a member of CTCI in order to see anything. I have tried to go to their sites but they won’t even load.