Brake balance

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Model T Ford Forum: Forum 2015: Brake balance
Top of pagePrevious messageNext messageBottom of page Link to this message  By Don Buelke on Tuesday, June 23, 2015 - 06:34 pm:

I've been trying to get both brakes to lock evenly and yet not have drag in neutral, but w/o success. I've readjusted the clutch linkage and have 1-3/4" movement in pedal from neutral to high speed as recommended (although some recommend 1" or 1-1/2".) Anyway, while up on blocks with brake rod clevises disconnected, the drum arms are slightly behind vertical and there is no drag. When I connect them at the most extended threads (they appear to meet the lever arms evenly) the RR wheel is free and the LR begins to drag, yet the brake lever is still forward ~15 degrees to where high gear starts to move the pedal. With the lever vertical both brakes drag moderately.

However, when the lever is pulled back all the way, the LR is immovable by hand, but the RR can still be turned with effort. When I do a test run on my gravel driveway, it corroborates this with the RR skidding, but not the LR. Brakes were relined with Kevlar and components were in good condition when the restoration was in process less than a 1000 miles back.

I could blame the drag at neutral on lack of sufficient wear-in yet, but what am I missing with the poor braking on the RR? Seems like it needs to be set shorter, but it's already dragging in neutral and that becomes worse if I shorten the link to lock the wheel on road testing.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Allan Bennett - Australia on Tuesday, June 23, 2015 - 07:29 pm:

Don, I presume you are talking about uneven braking on the handbrake. If one of the drums is not worn more than the other, I would be looking at the cams. They need to be the same or else one will spread the shoes more than the other, making that wheel brake more efficiently.

Hope this helps.

Allan from down under.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, June 23, 2015 - 07:42 pm:

Clutch and rear parking brakes don't have anything to do with each other except the parking brake lever put the car in neutral.

You need to set each side independent of the other to get both to stop the same.

When the parking brake lever is about straight up and down there should be no or very little drag on the parking brakes. The parking brakes should be fully locked up at about 4 clicks when pulling the lever back from straight up. With the rear end on stands disconnect one side and adjust the other till it locks up at the 4 clicks. Disconnect that side and do the other.

What year and are you sure you have the correct brake rods? Original parking brakes or outside brakes? If it's a 1925 and earlier the parking brakes were meant to hold the car and in a pinch help with the braking not for general stopping the car.

Kevlar is for internal oil cooled linings not rear brake linings. It needs to be the correct lining for brakes. It may be too thick anyway.


Top of pagePrevious messageNext messageBottom of page Link to this message  By JohnH on Tuesday, June 23, 2015 - 09:02 pm:

As someone who uses the rear drums for normal braking, I can say from experience you'll never get both brakes to lock up at the same time without having one drag all the time.
The problem is the handbrake lever is one side of the car. It has direct connection to the rear brake on that side. However, for the other side, you have the rod going across the chassis which as can be imagined twists slightly when the brakes are applied. You'd have to have the handbrake lever in the middle of the floor to make it apply equally.

In my situation with a RHD car, the right brake always comes on first. Nevertheless, the system as a whole works very well. If I have to do a quick stop and feel a swerve coming on, I'll use the foot brake as well.
While there is an accessory equaliser available for the back brakes, I feel it is risky should a back axle break and the wheel comes off. Then, you cannot stop the car as the remaining brake cannot be applied.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Norman T. Kling on Tuesday, June 23, 2015 - 09:13 pm:

This is how I adjust mine. With the rear axle jacked up on stands I put the parking brake lever all the way forward into the high position. I push the rods all the way back and adjust the rods to where the clevis pin will go in easily without moving the lever or bending the rod. Then I pull the brake lever back one notch at a time until I can feel a pull on the wheels when I try to turn by hand. Some people will use a torque wrench on the axle nut to be sure the pressure is even on each brake. If one of the wheels begins to apply the brake before the other, I tighten up the rod on the side that is loose by 1/2 turn. Test again. Continue adjusting the loose side by one half turn until both are equal. Then put in the clevis pins and cotter pins and drive the car on a level surface. Pull on the parking brake and the car should stop in a straight line. Anyway, that's how I do it.
Norm


Top of pagePrevious messageNext messageBottom of page Link to this message  By Don Buelke on Wednesday, June 24, 2015 - 06:12 pm:

My bad recollection on the Kevlar, it was the standard brake liner for 26-27 from Mac's. Norm, I did just what you stated and when I started pulling the brake handle back just a couple clicks both brakes started dragging. But the problem I have is as I proceed, the RR locks completely where expected, but although the LR gradually tightens, it never does lock, yet it is creating drag through the whole spectrum. It's like it could use another ~1/2" of adjustment.

I think Allan's suggestion that it might be uneven cams or drums might be the problem.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Stephen D Heatherly on Wednesday, June 24, 2015 - 06:49 pm:

Could be that the cams, bushings or drums are badly worn.

Stephen


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