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History 12-04-2021 07:56 PM

Front brake arms
 

Mine are over center toward the rear of the car. I know at that angle I have lost mechanical advantage. To remedy this will this procedure work?????,,,, I will unhook all rods from clevis and adjust them further apart so as to lengthen the rods. The slack that this creates, can it be taken up by the adjusting wedge? How do you know if you need a “pill” installed??

Thanks for any help with this.

SAJ 12-04-2021 08:28 PM

Re: Front brake arms
 

History, you need too lengthen the push rod that runs inside the kingpin, by putting a "pill" like a tiny cup shaped steel plug in the top of the actuator wedge the rod sits in. That will bring the arms forward, and you can then reinstall the rods and adjust to take up slack so the arms slope a bout 15 degrees forward.
This all depends on everything inside the drum being ax it should of course.
Your proposal is the reverse of what should happen- first you take up shoe to drum clearance with the square adjuster, then see where the arms sit, take up slack in the arms by pulling bacward sand adjust the rods so the pins just slip in the clevis.
This is for front brakes
SAJ in NZ
Apologies for not answering properly. I am watching the Australian Bathurst car racing as I type, and did not read your question right to the end!

History 12-04-2021 09:19 PM

Re: Front brake arms
 

Thanks for the reply,,, what you said is what I had originally thought but a fellow model a guy told me the adjusting wedge would take up all the slack. I couldn't get my brain around that completely but thought he knew what he was saying. What if I just put in new rods in the kingpins? Pills easier to install?



Quote:

Originally Posted by SAJ (Post 2082354)
History, you need too lengthen the push rod that runs inside the kingpin, by putting a "pill" like a tiny cup shaped steel plug in the top of the actuator wedge the rod sits in. That will bring the arms forward, and you can then reinstall the rods and adjust to take up slack so the arms slope a bout 15 degrees forward.
This all depends on everything inside the drum being ax it should of course.
Your proposal is the reverse of what should happen- first you take up shoe to drum clearance with the square adjuster, then see where the arms sit, take up slack in the arms by pulling bacward sand adjust the rods so the pins just slip in the clevis.
This is for front brakes
SAJ in NZ
Apologies for not answering properly. I am watching the Australian Bathurst car racing as I type, and did not read your question right to the end!


SAJ 12-05-2021 12:05 AM

Re: Front brake arms
 

History, new rods still might not be long enough, depending on where else there is wear.
Sometimes a blob of weld is applied to the vertical rod end or the top adjusting rod and filed smooth to fix the problem. 1 or 2 pills can be used or a thicker single pill made up to do the job.
For some this is easier than welding, but the pill(s) could escape from the pocket if anything hangs up inside the drum due to wear, lack of adjustment, dirt etc. A welded extension cannot do this. MIG welding puts on a hard deposit, but gas and stick can do the job if the right material is selected. The standard pills are only mild steel, so hardness is not a big factor, even so.
Flat head Ted (Ted Spain) shows how to make pills from sheet steel, using punch and hammer, on his web site, if you are unable to get them in time from a supplier.
While still watching the Bathurst racing I am trying to visualize how slackening the pull rod and bringing the arm forward with the adjuster could ever work in some circumstances. I cannot see how, but maybe someone else with access to the parts diagram could comment.
I don't like to criticize or disagree with a genuine brake expert without careful study which I cannot do at present
SAJ in NZ

nkaminar 12-05-2021 09:09 AM

Re: Front brake arms
 

History,

As you stated, the arms should be about 15 degrees forward. SAJ has the right approach. Adjust the pull rods for the right angle. Then try adjusting the brakes for a slight drag. If you cannot adjust them then you need a "pill" or longer push rods.

As SAJ stated, this all assumes that the brakes are in good shape and that the drums and shoes are not worn out. Someone has shortened the pull rods in an attempt to adjust the brakes so this suspects that some work may be needed to the brakes. The length of the pull rods, once correct, should not be changed and all adjustments done with the square adjusters.

Once you get everything fixed and adjusted, take the car out for a brake test. The brakes should not pull to one side and the rear wheels should leave a skid mark on dry pavement. The car should stop in 25 feet at 20 mph.

Bob Bidonde 12-05-2021 09:22 AM

Re: Front brake arms
 

2 Attachment(s)
These slides should help you:

History 12-05-2021 09:33 AM

Re: Front brake arms
 

Thank all of you for the replies. Those slides are wonderful, thank you BOB.

My rods may be shorter than the stock 7 1/4". I may weld those ends and smooth them up if that's the case or just get new rods. If close I'll use a pill or two. I see now that there's really no way the adjusting wedge could ever do what I need. Thanks again

Patrick L. 12-05-2021 11:11 AM

Re: Front brake arms
 

Quote:

Originally Posted by History (Post 2082450)
Thank all of you for the replies. Those slides are wonderful, thank you BOB.

My rods may be shorter than the stock 7 1/4". I may weld those ends and smooth them up if that's the case or just get new rods. If close I'll use a pill or two. I see now that there's really no way the adjusting wedge could ever do what I need. Thanks again





There ya go.

SAJ 12-05-2021 03:14 PM

Re: Front brake arms
 

Great slides Bob. Very useful.


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