Radius Rods Limit Brake Cross Shaft Travel

[Ian Curtis]

Tonight I noticed that the rotation of my service brake cross shaft is limited by striking radius rods (or the bolt connecting them, hard to tell exactly what touches first). This occurs before the pedal is on the floor, but not that much more pedal than the full brake adjusting stick from the Les Andrews book. Is this supposed to happen, and if it isn't is there a fix? How many degrees of travel should be required of the cross-shaft arm with properly adjusted brakes?

[H. L. Chauvin]

You might just need to properly adjust the brake rods and cross shaft arms to clear it.

I had a similar situation after having installed a 3:27 ring and pinion gear with a special speedometer adapter.

After purchasing & installing the adapter for the speedometer cable connection at the drive shaft, the service brake cross shaft was slightly contacting this protruding adapter when the brake pedal was fully depressed.

I just adjusted all of the brake rods where the service brake cross shaft arms are not exactly 90 degrees, (perpendicular to the ground), and the brake cross shaft does not contact this new protruding adapter ...... arms might be at 88-89 degrees in lieu of recommended 90 degrees when the brake pedal is not depressed.

Hope this helps.

[Tom Wesenberg]

My friend's 31 Wide Bed did the same thing until he had the frame straightened.
It had a bad sag at the rear motor mounts.

[john charlton]

Check the rear motor mounts . If you have "floater motor" mounts could be the rubber dough nuts have collapsed allowing the back of the engine to drop .Could also be bent frame . With the regular rear motor mounts it would be unusual for this to happen even if the rubbers were tired .

John in lovely sunny summers day Suffolk County England

[Mitch//pa]

What Henry said ,,, get the cross shaft arms 90 deg and set up the brakes... Once everything is adjusted the cross shaft moves very little to apply the brakes...

[Jacksonlll]

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The engine can sag with the std rear mounts if they are cracked. Check your mounts.

[Del in NE Ohio]

Is the car on jack stands with the weight off the suspension? I have seen a similar problem resolve itself when the car was removed from jack stands and wheels placed on the ground.

[Ian Curtis]

Originally Posted by H. L. Chauvin

You might just need to properly adjust the brake rods and cross shaft arms to clear it.

I had a similar situation after having installed a 3:27 ring and pinion gear with a special speedometer adapter.

After purchasing & installing the adapter for the speedometer cable connection at the drive shaft, the service brake cross shaft was slightly contacting this protruding adapter when the brake pedal was fully depressed.

I just adjusted all of the brake rods where the service brake cross shaft arms are not exactly 90 degrees, (perpendicular to the ground), and the brake cross shaft does not contact this new protruding adapter ...... arms might be at 88-89 degrees in lieu of recommended 90 degrees when the brake pedal is not depressed.

Hope this helps.

Henry / Mitch,

Yes I spent a few hours messing with the rods and resolved it to my satisfaction. The cross-shaft still contacts the radius rods when the pedal is slightly above the floor, but I've locked up the rears by the time the pedal is at half deflected, so I don't expect I'll ever need that much travel. It is amazing how it is a game of tenths of inches -- I didn't adjust the rods that much and the braking is just so much better. It's wonderful to finally be able to lock up the wheels!

Del, yes the contact was with the wheels on the ground.