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By Joe-JDC - 4 Years Ago
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I have adjusted my drum brakes to the nth degree, but the car still pulls or skids the tires in a hap-hazzard way if you have to brake suddenly. Sometimes it will move over a half lane, and that is not safe when trying to keep up with traffic at 65-70 mph. I have new Wilwood disc brake conversion kit for front brakes, and just want to know what master cylinder you have had good luck with on your conversions? I really don't want a booster for power brakes, but would like to keep them manual for now. I have converted older Mustangs for manual disc brakes and they worked fine, even my Mach I race car had manual disc brakes. They worked fine with a line-lock and stopped the car easily at 10.9s and 123mph. Joe-JDC
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By Vic Correnti - 4 Years Ago
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Joe, I used the Granada master cylinder and proportioning valve. I had to change the length of the rod from the brake lever to the master cylinder. I can't remember if I lengthened or shortened it. I don't see a need for a booster either, mine stops just fine without one.
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By Florida_Phil - 4 Years Ago
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I have converted a bunch of old Fords to front disk brakes. My current TBird has a complete Casco kit. Everything required came together, so I didn't have to piece out the parts. In the past, I have successfully used 1967-69 Mustang master cylinders both manual and disk. So far, I have not installed power brakes in any of my cars. They all stopped as desired. The Mustang master cylinder has the brake line connections on the driver's side. This can cause clearance issues in some cars. My 1957 Ford Custom did not have this problem. My 1955 Tbird did. You can use banjo fittings to get around this issue. You will need a proportioning valve. I bought mine from Summit. Jegs has them too. Some people have reported problems with the stock brake master cylinder lever. Be sure to install the button on the end of the rod. My cars all worked fine without shortening or lengthening the rod. Check yours and see. Converting to front disk brakes is one of the best upgrades you can do to these cars. Driving in today's traffic with 65 year old drum brakes is scary and dangerous.
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By Tedster - 4 Years Ago
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Driving anything is scary in "today's traffic", Driver Education as well as Driver Testing are mostly just distant memories in the minds of old cranks.
Pulling to one side on hard braking isn't something that can be remedied by shoe adjustment, that indicates a serious defect not inherent to drum brake systems but likely defective brake hose or wheel cylinders, brake backing plate wear, etc. I can certainly understand why disc brakes are preferred, but I would not want to drive a Tbird in heavy traffic, isn't worth the risk regardless of brake type. Too many nutbars out and out about.
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By DryLakesRacer - 4 Years Ago
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Wilwood has 2, a larger oval which I use, and a smaller one. I too prefer not to have a booster. I used their prop valve and a residual valve on their recommendation. They also said an adjustable Mustang pedal rod was easy to get the length correct. I bought everything from Summit because it was a good price and I live fairly close to Wilwood. Prestige Thunderbird in Santa Fe Springs Ca. sells an extended heat shield which I bought and applied an aluminum heat insulator and deflector tape from Home Depot. I also made a side heat deflector for the prop valve. If you look closely at the photo you can see both. My rear drum brakes are also wider than stock. My system is on the full size car and yours should work better because of your weight. For non booster brakes you should use a 7/8” MC.  |
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By KULTULZ - 4 Years Ago
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I have adjusted my drum brakes to the nth degree, but the car still pulls or skids the tires in a hap-hazzard way if you have to brake suddenly. Sometimes it will move over a half lane, and that is not safe when trying to keep up with traffic at 65-70 mph. I have new Wilwood disc brake conversion kit for front brakes
Exactly how does the car pull? Does it seem like rear brake lockup and the rear wants to come around?
Are the front discs overly aggressive causing the rear to come around or dart? Or does the car pull to one side with a hard application?
What WILDWOOD KIT did you buy (PN) and what is on there now for a MC?
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By Joe-JDC - 4 Years Ago
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It was the drum brakes that pulled indiscriminately or locked up, both in reverse and going forward. Just backing the T-bird out of the garage the front tires would lock up. Got embarrassing to move the car or go for a slow drive. Otherwise the rear brakes never locked up, and the emergency brakes hold just fine. I just didn't want to buy the wrong master cylinder for this Wilwood conversion kit. Some folks claim they run the stock master cylinder with no issues, but I am not so sure that is a good idea. Joe-JDC
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By 55blacktie - 4 Years Ago
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Wilwood and Dave (Drop 'em, Stop 'em) recommended 15/16ths master for non-power brakes. OEM master is 1-inch. Not having sufficient clearance for Wilwood's proportioning valve on battery side, I mounted it on the opposite side of the master on my 55 Tbird (no need to relocate battery). Plenty of room (Sanderson headers might help, and cooler/w ceramic coating).
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By DryLakesRacer - 4 Years Ago
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I believe the MC bore diameter depends on the pedal ratio. 2 companies I contacted prior to installing disc front brakes wanted it before suggesting any parts or kits. Since I had changed my complete rear end they also wanted the diameter of the wheel cylinders. Because mine came from a power brake vehicle I also needed to reduce their size.
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By DANIEL TINDER - 4 Years Ago
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Joe-JDC (11/6/2021)
I have adjusted my drum brakes to the nth degree, but the car still pulls or skids the tires in a hap-hazzard way if you have to brake suddenly. Sometimes it will move over a half lane, and that is not safe when trying to keep up with traffic at 65-70 mph. I have new Wilwood disc brake conversion kit for front brakes, and just want to know what master cylinder you have had good luck with on your conversions? I really don't want a booster for power brakes, but would like to keep them manual for now. I have converted older Mustangs for manual disc brakes and they worked fine, even my Mach I race car had manual disc brakes. They worked fine with a line-lock and stopped the car easily at 10.9s and 123mph. Joe-JDC
Joe,
Have you ruled out ‘contaminated linings’ from a wheel cylinder or axle seal leak? Are your drums reasonably fresh/turned to spec. & shoes properly radius ground? New/identical cylinders & hose?
I once made the mistake of installing dissimilar brake parts piecemeal. No amount of adjustment could ever rectify.
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By KULTULZ - 4 Years Ago
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t was the drum brakes that pulled indiscriminately or locked up, both in reverse and going forward. Just backing the T-bird out of the garage the front tires would lock up. Got embarrassing to move the car or go for a slow drive. Otherwise the rear brakes never locked up, and the emergency brakes hold just fine. I just didn't want to buy the wrong master cylinder for this Wilwood conversion kit. Some folks claim they run the stock master cylinder with no issues, but I am not so sure that is a good idea. Joe-JDC
We have to know exactly how the car is built now.
What MC are you presently using and do you have any valving at all (metering - proportioning - residual)? OEM drum brakes on the rear axle?
What is the PN of the WILDWOOD KIT you mounted on the front axle?
Whoever said that they run a drum/drum single reservoir MC on a disc/drum setup ain't too smart (unless it is an early dual outlet DISC/DRUM single reservoir).
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By Joe-JDC - 4 Years Ago
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I have a degree in Automotive, and a degree in Aircraft Maintenance, and taught Automotive at Central Texas College, Europe campus, retired Aircraft Master Instructor from USAF, so not a novice about brakes and suspension alignment issues, rebuilding transmissions, rear differentials, engines, etc. I just wanted to know what you folks had used that actually worked before removing my master cylinder and wasting time and money. This car has the alternator conversion, AC added, three speed OD. Original rear end, brakes. I went through the front brakes, wheel cylinders, brake shoes, small parts, drums, and refurbished everything, adjusting until stopping wheel, backing off, etc., according to standard practice, and the brakes still will grab unevenly. Shoes arc'ed, same width, and same material matrix. Wheel bearings packed/adjusted. The front steering is tight, new shocks, radial whitewall tires, tire pressures equal. Manual steering with stock steering wheel. It drives nicely under most circumstances, and it gets thumbs up. I have the 345 Y ready to install with 5 speed Tremec, and I prefer to have the brakes rock solid before doubling the horse power.
Wilwood 140-12922 brake conversion kit for '55 Thunderbird.
Thanks for your replies and help.
Joe-JDC
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By Lou - 4 Years Ago
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It sounds like you have a seal leaking grease onto the brake shoe. I'm speaking from experence.
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By KULTULZ - 4 Years Ago
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Well, you won't answer any questions but let me know this. Are you using the OEM single reservoir drum/drum MC on this conversion?
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By Cliff - 4 Years Ago
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I think Joe knows just what he's doing, and I think his car is still stock, looking for pointers before changing parts, I do this sometimes so I don't have to reinvent the wheel, I'm removing a Ford O and replacing it with a Cruise O in a 1957 Fairlane, I got a lot of talk about things I did not ask, and only one good answer. As for Joes car I have the most luck by changing the whole system from a later car, My sons car is a 1957 Fairlane 500 it's getting front Disc, master and rear drums from a 1973 Galaxy (doing it now).
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By paul2748 - 4 Years Ago
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You could have different material on each side for the brake shoes. Has a wheel cylinder blow out while traveling in Oregon at a Tbird show. Got new shoes for the blow out side and replaced the cylinder from one of the other guys at the show. After that the car pulled terribly - different material side to side. Next day went out a bought a omlet set of shows for both fronts and made the change at the motel. Fine after that.
I would contact Wilwood for their recommendation - after all it's their brakes and they should give you the proper info for there system. Then no guessing.
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By KULTULZ - 4 Years Ago
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I think Joe knows just what he's doing, and I think his car is still stock, looking for pointers before changing parts ...
I am not questioning his knowledge and/or abilities, I am curious as to why the car jumps lanes.
He mentioned that he has heard that others have used the original MC with good results. All I want to know is how and why someone would make such a statement. Whatever the OP wants to use on his street driven car is his business.
Just the addition of a dual reservoir disc/drum MC may or may not fully cure whatever the problem(s) is.
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By DryLakesRacer - 4 Years Ago
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It is my thoughts are a dual master with an adjustable proportioning valve is the general fix for vehicles which were not specifically built with a disc/drum or disc/disc system. Factory units may have the valve but are usually not adjustable from what I have seen. This is why taking a complete system from a single donor car may work so well. I followed the instructions for the Wilwood system of adjusting the prop valve and everything worked as I believed designed. I’ve had it on for a year and needed 2 panic stops. Not a high speeds but it worked perfect both times and accidents were avoided.
With what I’m reading the entire system to the rear drakes should be carefully looked at, specifically the lines and wheel cylinders. I’m not sure on the shoe issue. I’m sure Joe has done all this and I’m just thinking out loud. When your not happy with brake it’s imperative that the problem and solution be found.
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By KULTULZ - 4 Years Ago
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What I have read from the text is that the original MC was used with the front disc upgrade.
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By Joe-JDC - 4 Years Ago
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Not yet. I asked for suggestions for what master cylinder folks have used successfully that have done the conversion. I have not changed the master cylinder yet, but will before bleeding the brakes and first test drive. I will use a proportioning valve, double flare the tubing, etc.. I have done the rear disc brake conversion on my Fox Mustang GT using a proportioning valve. Joe-JDC
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By Joe-JDC - 4 Years Ago
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Wilwood says to use the round stock master cylinder and remove the residual pressure valve. That prevents the brakes from holding pressure. So, I may go that route first. They do not recommend a proportioning valve be installed. Joe-JDC
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By KULTULZ - 4 Years Ago
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Wilwood says to use the round stock master cylinder and remove the residual pressure valve. That prevents the brakes from holding pressure. So, I may go that route first. They do not recommend a proportioning valve be installed. Joe-JDC
You need to stay away from WILDWOOD TECH if you were told this.
With all of your credentials you must have theory/tech literature on how a disc/drum brake system is designed, plumbed and operates.
You need a correct style dualing MC, plumbed with correct valving for the system, period.
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By paul2748 - 4 Years Ago
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If Wilwood told you this, I'm sorry that I recommended you call them. Front discs and rear drums require a residual pressure valve, but at different pressures for the front vs the rear. And most likely a proportioning valve for the rear.
In a factory disc/drum setup, they usually use combination valve which does both functions.
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By KULTULZ - 4 Years Ago
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Front discs and rear drums require a residual pressure valve ...
Front disc does not require a RPV unless the MC is located under the caliper plane and that is a 2# to prevent fluid drain-back (gravity) to the MC.
A 10# residual valve in the disc circuit will cause pad drag.
That is what caused the front brakes to drag when backed out of the garage,
If you notice, these so-called brake kit suppliers all have the same song and dance and conflict with one another with tech advice. Some are outright dangerous.
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By KULTULZ - 4 Years Ago
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If Wilwood told you this, I'm sorry that I recommended you call them.
Not your fault. You would think a company as large and successful as WILDWOOD would have a knowledgeable TECH to advise as to how and why. And it is not only WILDWOOD.
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By Lord Gaga - 4 Years Ago
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[quote]KULTULZ (11/11/2021)
You would think a company as large and successful as WILDWOOD would have a knowledgeable TECH to advise as to how and why.
Wilwood tech people and the sales dept. are worthless. I'll NEVER buy another one of their products after wasting more that a month trying to get an out of true rotor issue resolved!
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By KULTULZ - 4 Years Ago
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Wilwood tech people and the sales dept. are worthless. I'll NEVER buy another one of their products after wasting more that a month trying to get an out of true rotor issue resolved!
Well, I am at a disadvantage as I never had the money to go with high dollar store bought. My cars were more or less JUNKYARD DOGS. And I understand going that way if one is building a show car or resto-mod. But there is not much FOMOCO didn't offer to do the same thing. The trick was knowing what car to pull it off of.
And now much of the stuff is off-shore adding to the problem(s).
I recently was trying to cipher why the RPV was dropped (working on ABS SYSTEMS) and I had one well known brake kit company TECH tell me the weight of the fluid (gravity) keeps the wheel cylinder cups from cocking after brake release.
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