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Hi People, I am a new 75 year old with a 41 olds that has the usual 455 engine and turbo 400 out of a 68 olds 98 with only 26k miles on it.A ford 9" rear end out of a 78 bronco. Don't claim to knoow everything so need a little help. The 41 still has the origional front end with power brakes from the 68. The brakes always pull to the drivers side no matter how I adjust them. Is there a way to fix this? I would put disc brakes on it but don't know if there is a way to do this. Second proble is a rythamic drumimg vibration in the drive shaft at 40 to 50 mph. Could it be the slip yoke is not far enough in the transmission It was only 3" long so there is 2" in the trans. and 1" outside. Can I balance the driveshaft myself? Sorry to ask so much at one time. Thanks silverfox.3
 

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fay ellis said:
Hi People, I am a new 75 year old with a 41 olds that has the usual 455 engine and turbo 400 out of a 68 olds 98 with only 26k miles on it.A ford 9" rear end out of a 78 bronco. Don't claim to knoow everything so need a little help. The 41 still has the origional front end with power brakes from the 68. The brakes always pull to the drivers side no matter how I adjust them. Is there a way to fix this? I would put disc brakes on it but don't know if there is a way to do this. Second proble is a rythamic drumimg vibration in the drive shaft at 40 to 50 mph. Could it be the slip yoke is not far enough in the transmission It was only 3" long so there is 2" in the trans. and 1" outside. Can I balance the driveshaft myself? Sorry to ask so much at one time. Thanks silverfox.3
Welcome to hotrodders. As far as the brakes go, it sound like the brakes are not getting equal pressure from the master cylinder. You may have to install a master cylinder with a built-in proportioning valve or install an external one.
The driveshaft question: Is the 1" sticking out with the car on the ground or jacked up? Make sure it is sitting on all 4 wheels and then measure it. It is possible to staic balance the driveshaft yourself with the proper equipment but you really should have a driveline shop balance it.
 

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Hello Fay and welcome :thumbup:

My mind works in mysterious and complicated ways and I always seek out the most difficult solutions to problems. Don't know why, it's just the way I'm wired. So, as soon as I read your post, my mind jumped to the wheelbase being unequal, driver's side shorter, even though the steering has been adjusted to steer the car straight ahead in brakeless running. Again, I might be full of mush, but that's what I visualized, particularly since the car has had a 9" transfusion and the diff could be skewed relative to the centerline of the car. And I'm not certain this would make the car pull left, it just seems like it would in my mind. This hypothesis assumes that the drums are the same internal I.D. and the same size and width shoes are being used, as well as making certain the primary and secondary shoes are installed in their proper respective positions and that tires are the same size and aired to the same pressure. It further assumes that the same size wheel cylinders are being used front/front and the same size calipers and pads are being used rear/rear.

If all that stuff checks out, I might do the following. Drive the car into the shop in a straight line. Jack up the front and rear by the axles and place blocks under the axle on each of the four corners so that the car weight is on the axles. Remove wheels/tires and measure from the centerline of the front spindle to the centerline of the rear axle on each side of the car to verify wheelbase is within 1/8" or less. Do not change the position of the steering wheel between driving it in and doing the measurements.

As far as the imbalance problem, place your floor jack under the pig, raise the rear and remove the wheels and tires. Chock up the differential on each side with appropriate jackstands or whatever you have on hand that is safe to use. Fire the motor and drop her in gear. Accelerate the motor to come up to the 40 to 50 mph on the speedo where you are having the problem. Vibration still there, it ain't the wheels and tires. Vibration gone, have the wheels/tires balanced. If the vibration is still there, put a drain pan under the transmission tailshaft and remove the driveshaft. There are plastic cups available to stick into the housing to emulate the yoke being there so you don't blow fluid all over the place. Once you pull the driveshaft, stick one of these cups in place of the yoke and secure it with duct tape. Run the motor up to 40-50 in gear. Vibration gone, it's the driveshaft. Vibration still there, it's the transmission, torque converter, flex plate or reciprocating assembly in the motor.
 

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Sometimes in rear end swaps the installer might not have matched the pinion u joint angle and tail stock u joint angle they need to be the same or vibration will occur. If the tail has 3* then the diff needs 3* the other way, or what ever your set up is. Since there is a bit of retro fitting in the 9" swap maybe this is the problem.
 

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Barn Owl said:
Sometimes in rear end swaps the installer might not have matched the pinion u joint angle and tail stock u joint angle they need to be the same or vibration will occur. If the tail has 3* then the diff needs 3* the other way, or what ever your set up is. Since there is a bit of retro fitting in the 9" swap maybe this is the problem.
Good point. I forgot about that. Thanks.
 

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Welcome aboard. Post photo's of your car, if possible!

A way I have found useful to "see" exactly what the brakes are doing, is to find a secure spot to do this in- might be the hardest part of the deal, has to be somewhere that has space to both sides, front and back, no people around.

The surface needs to be smooth, flat and slippery enough that the brakes can be locked up w/o a lot of drama. A beach (Daytona is perfect :D ), a deserted construction site, where ever.

Drive to 30 mph or so and hit the brakes firmly, then stop and walk back and look to see where each tire locked up. They should be adjusted to where the fronts lock up at the same time, the rears should lock up at some point after the fronts. Also at the same time.

A few thoughts:

In a situation where you have the car pulling to the left, you will almost surely see that the left side has locked first.

The cause of this can be air in the line on the right side- the air will compress THEN the fluid will actuate the brakes if any air hasn't been bled from that right side. This causes the left brake to actuate before the right one and can cause the pull to the driver's side.

I'm basing some of what I'm saying here on you having used the power brake booster and MC from the '68 on the original drum brakes of the '41.

Drum brake apps- The springs and hardware that hold the shoes to the backing plate and that serve to return the shoes to an "at rest" position also need to be replaced as a set- both sides at the same time.

The master cylinder for drum brakes usually have residual valves built in. If you've not installed residual valves (and you are using the '41's front drum brakes), you will likely need to add them. If you have the '68 power brake booster, master and rotor/calipers, the residual valves could be faulty.

Besides the residual valves, the flexible lines from the chassis to the slave or calipers needs to be replaced if they're original. They can deteriorate internally, the inner lining will actually block the flow of brake fluid when this happens. Also check the clamps that hold the flexible lines from contacting anything- these clamps can get bent or rusted up in their ID and that can pinch the flexible lines.

Drum/shoe or rotor/pad contamination- often a brake fluid-soaked shoe will lock up (grab) before a dry one, and no amount of cleaning ever really restores it back to a "before wet" condition in my experience. Any grease from a bad bearing seal will foul them, too. This can make that brake lag behind the others.

The slave cylinders or rotors will sometimes lag behind each other, especially if at some point one was replaced and the other side was not replaced at the same time.

Obviously, the adjustments have to be such that the brakes work in unison, but w/o all the components working together at the same time, the brakes cannot work evenly.
 
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