E-Bodies.org Cuda Challenger Forum

Technical Shop => Wheels, Tires, Brakes, Suspension & Steering => Topic started by: Dakota on November 14, 2020, 06:00:51 PM

Title: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: Dakota on November 14, 2020, 06:00:51 PM
I have a little too much travel in my brake pedal before the brakes kick in.   The brakes work great once that point is reached.   I have the same booster as what's shown in this picture that Cody posted a while back. 

Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: edison1970 on November 14, 2020, 06:26:59 PM
Yes. It is adjustable.  Be careful not to go too far. The brakes will drag.  I have the same issue with mine.
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: Dakota on November 14, 2020, 06:30:03 PM
Thanks!
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: anlauto on November 14, 2020, 07:46:18 PM
Quote from: edison1970 on November 14, 2020, 06:26:59 PM
Yes. It is adjustable.  Be careful not to go too far. The brakes will drag.  I have the same issue with mine.

Here's a question about this...do you think it's possible for the rear brakes to "drag" and not the front brakes if this rod is adjusted incorrectly ?

Keep in mind the reservoir for the front brakes is closer to the booster ...
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: edison1970 on November 14, 2020, 09:52:33 PM
I'm not sure about the answer to your question but I adjusted the rod out too far and about a quarter mile from my house, I  had to pull over and readjust it. I pushed in the clutch and the car came to a halt. Front brakes were smoking.
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: Chryco Psycho on November 14, 2020, 11:15:01 PM
The front brake reservoir is closer to the firewall so it is more likely that hte front brakes will drag , I can't see the rear brakes dragging without the front as the piston for the front brakes has to move to activate the rear brakes .
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: anlauto on November 15, 2020, 04:46:12 AM
Quote from: Chryco Psycho on November 14, 2020, 11:15:01 PM
The front brake reservoir is closer to the firewall so it is more likely that hte front brakes will drag , I can't see the rear brakes dragging without the front as the piston for the front brakes has to move to activate the rear brakes .

That's what I thought too, thank you. :drinkingbud:
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: VCODE on November 15, 2020, 07:23:38 AM
Dakota, there is a tool made for getting the correct measurement. About .030 between push rod and piston clearance.
Bob
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: Burdar on November 16, 2020, 05:39:12 AM
Incorrectly adjusted rear brake shoes will cause a low pedal also.  The shoes should have a slight drag on the drum when they are adjusted correctly.

As for the booster pushrod...

I measured the distance from the master cylinder mounting flange to the bottom of the master cylinder piston.  Then I adjusted the pushrod to match this measurement.(from the tip of the pushrod to the booster mounting flange)  Once the gasket is installed between the two parts and "crushed" you'll have a little bit of clearance.  Right or wrong, that is how I did it.
Title: Re: Is the brake booster pushrod adjustable? (70 Challenger)
Post by: Dakota on November 16, 2020, 11:32:11 AM
Thanks for all the replies. 

I made a rough adjustment this afternoon.  Much better!  Best I can tell, there's no drag. 

I will probably get one of the measuring tools to make sure it's correct.  Since I didn't want to disconnect the brake lines from the master cylinder, there's not a lot of room for my caliper. 

I was pleasantly surprised at how easy it was to adjust since the pushrod can be partially removed from the booster to get better positioning with the tools and the coiled brake lines provide a bit of "give" for moving the master cylinder.