620 rear brake drum wont fit anymore

[Eric]

I took off my brake shoes on my 620 and installed new rear brake cilinders and parking brake cables, refitted everything but now my drum wont fit over the shoes anymore.

What am i missing here? Parking brake in not engaged, cables are not tight, the adjuster wheel is turned completely upwards.

Edited March 23, 2020 by Eric

[banzai510(hainz)]

This a 510?

center the shoes

also the brake adjuster make sure the wedge is square and not pushing on the shoe

[datzenmike]

 Yeah probably the cylinder needs to be shoved over to the middle. It has clips on the back holding it in place and once on is self centering

[Eric]

No its a 620, sorry. I tapped the cylinder back to the center already but still it doesn't fit, its only a mm or so but the drum just wont go over it and i don't want to use the big hammer on it..

[datzenmike]

Then there is something different with the wheel cylinder. I had this happen on my B-210. I ground a few mm off the ends of the shoes where the contact the wheel cylinders and the adjusters. Perfect fit.

 

I think the new friction material was thicker than the stock. This was the mid '70 when Canada was just recently changed over to metric from inches

[Eric]

Grinding off a bit of the shoe would be a solution, but it came out like this so i can't stand it if it doesn't fit back in 🙂

[datzenmike]

Totally agree. I tried everything to get mine on and didn't do this lightly. Everything was the same and the only thing I could think of was the shoe material was thicker.

[wayno]

I understand that you say the e-brake cable is loose and it likely is loose without the drum on it, but have you pushed the arm that has the cable connected to it all the way to the settled position, can you or does the cable get tight?

I had this issue a very long time ago and it turned out the e-brake cable adjustment was too tight, I completely disconnected the cable from the center pull and let it lay on the ground and the drum slid on fine, then I adjusted the the e-brake cable so I could get it connected to the center pull and adjusted it so it worked properly again.

 

I just didn't understand why I could not get the drums back on, all I did was put new brake shoes on, the e-brake was not engaged, everything was loose, and turned out to be the e-brake cable was adjusted for worn out brake shoes.

[Eric]

I tink the cable is loose enough but it never hurts to give it a try, thanks @wayno

[datzenmike]

Are both sides not fitting?

 

Have a look at where the lining is on each shoe. If you have one where the lining is farther away from the wheel cylinder, this has to be the leading shoe and should be mounted in the direction the drum turns. A shoe with lining material closer to the wheel cylinder goes to the side where the drum is turning towards the wheel cylinder.

 

 

This is the right rear of my 710 wagon. Note the wheel cylinder is at the bottom and not the top like a 620. The shoes are very worn but if you look closely the left bottom lining is farther away in the direction of turning. (which is clockwise) The other side is turning toward the wheel cylinder so it's closer.

 

 

This is how the new ones went on...

 

 

It's possible to have two leading shoes on one wheel and trailing on the side of the car or leading and trailing reversed. If leading and trailing are reversed the car will stop better backing up than going ahead.

 

If all your shoes look the same then this won't matter.

 

Not sure if this will even help or not.

[mklotz70]

Did anything change with the brake pedal?  Is the return spring on?  Is the wheel cylinder completely  compressed?  If the brake pedal got pushed or it settled due to no return spring, it could have pushed the wheel cyl out a bit while the shoes were off.  Crack the bleeder valve open to get it compressed fulled.  If it's fully compressed, then Mike and Wayne have already brought up anything else I could think of. 

[Eric]

I used the shoes that were already in it, on the 620 one of the shoes has an extra lever for the handbrake. so there is no switching sides by mistake. unless the previous owner had the handbrake lever installed on the wrong shoe. i will check that.

The brakes have no brake fluid in them yet. So any change of the pedal would have nothing to do with the shoes. the return spring is on, and the cylinder is completely compressed. 

 

I only took this one picture of the finished result, the lining appears to be the same on both sides.

 

[wayno]

So is that spreader bar an inch or two under the brake cylinder loose or tight?

Is the old brake cylinder exactly the same size meaning the spread between the two shoes where they rest against the brake cylinder in the grooves?

[datzenmike]

I assume the wheel cylinder has not been bled yet and is fully compressed by the return springs.

 

Perhaps removing the adjuster and disassemble and clean and 'grease' it it? They are at the bottom and get soaked and corroded. Perhaps the adjustment isn't quite at the bottom yet?

 

Are both sides not fitting?

[thisismatt]

8 hours ago, Eric said:

I used the shoes that were already in it, on the 620 one of the shoes has an extra lever for the handbrake. so there is no switching sides by mistake. unless the previous owner had the handbrake lever installed on the wrong shoe. i will check that.

The brakes have no brake fluid in them yet. So any change of the pedal would have nothing to do with the shoes. the return spring is on, and the cylinder is completely compressed. 

 

I only took this one picture of the finished result, the lining appears to be the same on both sides.

 

Doesn't this look like two trailing shoes?

Edited March 23, 2020 by thisismatt

[Eric]

I don't know @thisismatt this is how it was when i bought it so i put i back like that. have never driven the car. trailing shoe is the shoe with or without the handbrake lever attached? Both shoes do look exactly the same from this picture.

 

[Eric]

Just checked the shoes, all 4 of them have the same lining. i have 3 spare shoes and they have the same lining as well. 

[Eric]

 

 

lining is the same on all shoes, so maybe it needs to be like that?

[datzenmike]

Yes that appears to be the way they are. On checking I can see in diagrams that this is so, however, before June '76 they are listed as primary and secondary shoes and have separate part numbers for the linings and the shoes themselves. After June '76 there is no mention of a difference and listed as 44060-B3025 presumably for both L&R.

Primary shoes are 44060-B3000

Secondary shoes 44070-B3000 

 

Depending on your year of truck maybe there is a difference prior to June '76 and after there is not? Maybe the linings changed thickness?

 

 

On 3/22/2020 at 9:06 AM, Eric said:

Grinding off a bit of the shoe would be a solution, but it came out like this so i can't stand it if it doesn't fit back in 🙂

 

 I love these problems. A chance to dig in and learn something. Hopefully solve it too.

 

 

Short of this, the wheel cylinders must be different, the new shoes are, or the adjuster is not all the way in. 

 

 

[Eric]

The truck is a 79, the spare brake shoes are from a truck with drums on all four corners and they are the same as the shoes on my truck. the only thing i didn't check yet is the size of the wheel cylinders.The adjusters are all the way in. 

Edited March 25, 2020 by Eric

[MikeRL411]

Drum brake shoes were sold over sized so that when the drums were machined and its new diameter measured, the shoes could be curved in the brake lathe to fit the new drum diameter.  I guess us old farts are the only ones who remember this step.

[datzenmike]

I remember recently, that this was mentioned in another post.

[MikeRL411]

19 hours ago, datzenmike said:

I remember recently, that this was mentioned in another post.

 

Yes.  Mine.  Apparently no one knows how to "search" these days.

[Eric]

Completely unbolted the parking brake cables from the center of the truck. drum slide over the shoes without any problems.

so now the drums are on, but i cant refit te parking brake cables because the drums would get stuck 🙂

let's figure that out tomorrow.

[datzenmike]

 That would suggest that they are not backed off all the way at the E brake adjuster or the e brake handle is not all the way in under the dash.