No Rear Brakes?

[manic]

I'm thinking about removing the rear drum shoes temporarily for a couple of test runs. I'm trying to tune the fuel pump but I would like to eliminate the drag from the rear drums first. I put new drums, shoes, cylinders, springs but the aftermarket shoes are just slightly too big so are giving considerable drag.

Can I run with the rear brake shoes out or will it kill my front brakes or damage my rear cylinders?

[justinc]

Kidding right? Driving on the road without operational brakes, especially intentionally disconnected, is a bizarre activity.

Think very carefully about what could happen, and the liability would be placed squarely on you should anything go pear shaped.

JC

[manic]

Kidding right? Driving on the road without operational brakes, especially intentionally disconnected, is a bizarre activity.

Think very carefully about what could happen, and the liability would be placed squarely on you should anything go pear shaped.

JC

Its a question, no joke. So your saying if rear drum shoes are removed the front brakes no longer work?

I only want to gauge the level of drag that I currently have by comparison. So lets calm this down - for a low speed test run on private grounds is any damage done without having the rear shoes in - will the front brakes still work?.

[justinc]

No, you will have no effective brakes as the pedal will go almost to the floor to take up the travel of shoes with no drums etc. Best bet then is to do as you were going to do and remove the shoes/ or drums, and make sure you clamp off the rear brake flex line. You will then get front brakes ONLY, and a hard brake pedal.

And I am happy you are not doing a test on public roads:)

JC

[manic]

No, you will have no effective brakes as the pedal will go almost to the floor to take up the travel of shoes with no drums etc. Best bet then is to do as you were going to do and remove the shoes/ or drums, and make sure you clamp off the rear brake flex line. You will then get front brakes ONLY, and a hard brake pedal.

And I am happy you are not doing a test on public roads:)

JC

Ok I thought that might be the case... hmm maybe its better if I take them out and get them machined locally -whilst i wait - if possible. Is it common to have brake shoes ground down a few mm? I don't have a grinder, but would an abrasive attachment on the end of a drill be worth trying?

M.

[justinc]

Take the drums and shoes in to a brake place to be properly radiused, it's where they grind away the friction material to match the radius of the drum. DON'T attempt this at home as the dust is very dangerous, even though it is now asbestos free.

JC

[Blknight.aus]

before you do that....

check the orientation of the shoes....

if you have the generic non-leading/trailing pad position sets its easy to put them in the wrong way around the only difference is the pin position

one side will almost always be rubbing till the pad meat is ground away the other side will work normally till some of the pad meat goes and then it wont hold adjustment.

[BilboBoggles]

I'm thinking about removing the rear drum shoes temporarily for a couple of test runs. I'm trying to tune the fuel pump but I would like to eliminate the drag from the rear drums first. I put new drums, shoes, cylinders, springs but the aftermarket shoes are just slightly too big so are giving considerable drag.

Can I run with the rear brake shoes out or will it kill my front brakes or damage my rear cylinders?


I would have thought that if the drums were causing enough drag to be significant enough to affect fuel pump flow rates, they would have caught fire and burnt after your first 100kmh trip on the freeway.

I reckon you can't gauge drag by just jacking up a wheel and turning it is as that is very different to running drag where wheel runout tends to throw the shoes from contact with the disc or drum..

[manic]

before you do that....

check the orientation of the shoes....

if you have the generic non-leading/trailing pad position sets its easy to put them in the wrong way around the only difference is the pin position

one side will almost always be rubbing till the pad meat is ground away the other side will work normally till some of the pad meat goes and then it wont hold adjustment.

I was pretty sure they were on correctly when I last dealt with them back in April
http://www.aulro.com/afvb/technical-chatter/149676-rear-drum-brake-adjustment-2.html#post1674324

I suppose I should have one more crack at getting them to sit pretty before going for machine.

[manic]

I would have thought that if the drums were causing enough drag to be significant enough to affect fuel pump flow rates, they would have caught fire and burnt after your first 100kmh trip on the freeway.

I reckon you can't gauge drag by just jacking up a wheel and turning it is as that is very different to running drag where wheel runout tends to throw the shoes from contact with the disc or drum..

I have not done anything near 100kph yet, I would like to though! You are right, the wheel does not turn by hand when jacked up but it also holds the car from rolling down the drive with the hand brake off. It is significant, the drums get hot after a slow 500 meter crawl around the block.

My fuel pump has been fiddled with in the past, so I have it set low and set up an EGT probe. I wanted to increment performance to a safe, low smoke level with some test runs but I cant with the brake shoes rubbing as they are. My first test it couldn't pull 2nd gear so I was wondering how much of that was pump settings and how much brake rub.

Anyway I only wanted to know if I could get some test runs in with the rear brake shoes removed.. I am eager to find out how it runs you see...

:bangin: hmmm fix brakes first?! suppose I better.

[JDNSW]

.....
I reckon you can't gauge drag by just jacking up a wheel and turning it is as that is very different to running drag where wheel runout tends to throw the shoes from contact with the disc or drum..

This is not the case with drum brakes. With these rear brakes, one leading/one trailing, wheel movement will tend to throw one shoe away from the drum, but the other one will be dragged into greater contact. Wheel runout will have no effect on drum brakes unless it is way out of spec. As the drum heats up and expands, the drag will, however, decrease.

John

[sdt463]

:bangin: hmmm fix brakes first?! suppose I better.[/QUOTE]

Good idea me thinks. :D:D

[jimr1]

Hi, if you take your rear shoes out you will be lucky to get 2 pumps on your brake pedal. Your rear pistons will pop out and you will loose your brake fluid, leaving you with no brakes at all, so dont go there!

If your brakes are binding they will get very hot with only a short drive o check that they are fitted correctly, then back them off so that your rear wheels spin and then you can do your test, regards Jim:)