Front walks around while braking

[metalmonkey47]

'76 620 stock front drum/rear drum

 

Everything's been replaced, short of the drums. 

 

 

I haven't been able to figure this one out. Last night driving it home from a meet, I noticed it's been pulling VERY hard to the right side as if the driver front brake isn't doing anything. I re-adjusted it last night because it was so damn loose that I didn't feel it was working hardly at all. 

 

Drove it today, had to jump on the brakes at nearly 70mph and the truck pulled so hard right that I almost lost the steering wheel. It's very inconsistent, sometimes it doesn't pull to the right, sometimes it brakes perfectly fine. It seemed a little better after the adjustment last night, still pulls to the right even though I balanced the adjustments from side to side. After driving it again today, I feel like it's gotten a tad bit worse again. 

 

Details:

 

If I'm laying on the brakes as hard as I can, the front end will walk around from left to right. Once the brakes heat up, I have a little more stopping power, but I can hear every damn drum howl from major warping. 

 

I've been over every inch on the front brakes and haven't found a reason why either side would brake differently. Everything is identical from side to side, and everything is less then a year old.

 

Hydraulics are working without leakage. Steel lines aren't pinched, and I'm getting fluid through the bleeder (no clog on drivers side wheel.) My fluid is even fresh and clear as it comes from the bottle. 

 

Occasionally I'll hear popping from the drum, as if the shoes aren't releasing. I've heard that as long as I've owned the truck, and it's never gotten any better even after replacing everything. 

 

I have no play in the steering except a tiny amount in the gear box, as needed. 

Edited April 21, 2013 by metalmonkey47

[wayno]

I have always had this issue with datsun 521 front drum brakes, I was never able to completely fix it, but check all your bushings, my biggest issue was the driverside UCA spindle/mount shaft, it was wore out which means it was loose, I always did a counter clockwise spin in an emergancy stop, every freaking time, I got so sick of it, that I did my disc brake conversion before Ratsun even existed, it worked great for several years till I started using it as my work truck, then it started having issues with that type of work load, but I believe I have finally got it sorted out, since the last fix, I have not had any issues at all, it's been one of my longest stretches without any issues so far.

[datzenmike]

Check your tension rod bushings.

Check alignment (toe)

[metalmonkey47]

I've gone across everything now, no play. All bushings feel tight with no play, only issue right now is idler arm play.

 

 

I'm gonna re-bleed them again, because it's starting to feel like the driver front brake isn't working AGAIN.

 

 

Thank god for my raise/promotion at work. I'm about to start buying up parts for front disk brakes. 

[datzenmike]

Take the drums off and look at the shoes. There are leading and trailing shoes. Maybe one side has the shoes reversed???

[metalmonkey47]

I'm pretty sure I got them right when I put them on last, but I'll get a pic of the shoe orientation when I get a chance next. 

 

I know that's been discussed quite a bit here, and I don't recall anyone ever coming up with an answer on what the correct orientation is. 

[datzenmike]

The shoes interchange front to back but the friction material is placed differently. You may have all the trailing shoes on one side or one side reversed.

 

I think the front shoes (leading) have the friction material closest to the wheel cylinder and the trailing are rotated down closer to the adjusters.

 

Ever notice that the brakes work better going forward than when backing up? I think this is why.

[metalmonkey47]

Alright, I am totally lost! I'm finding conflicting information everywhere. 

 

Mike, I replaced the shoes just an hour ago, since I got a bitchin warranty on these things. 

 

 

Now, as far as shoe orientation goes, I installed the the same way they were and the only way they made sense. Like you said, material closest to wheel cylinder. 

 

DRIVER: 

 

This is how it came off, and went on. 

 

 

 

Now on passenger, I forgot to take a picture, but i somehow managed to get the leading shoe on the rear on the other side. Weird, considering if that was the case it should pull LEFT right??? I corrected that and stuck the drum on, and the damn thing was so tight it wouldn't spin (same orientation as above) even with the adjuster spun all the way in. Now, I don't know if anyone recalls, but about a year ago I had an issue with the drivers side brake dragging. I went through everything and finally flipped the shoes around and it was fine.

 

Fast forward to today, and I had the same issue, except putting the shoe in the OPPOSITE position as I installed the drivers made it work??? Now it pulls left, and I'm absolutely lost. I have got to be doing something wrong, or getting shitty parts.  (Doubt that) 

 

I looked up some diagrams, and this link here shows the opposite of what I've already done here. Shows the shoe material is installed with the lining closest on the REAR side away from the piston on the wheel cylinder? 

 

 

I'm too tired to be working on this thing. 

[metalmonkey47]

bump

[metalmonkey47]

bumpppp.

 

 

Another thing I've noticed is that no matter how hard I mash the pedal, I CANNOT lock up the tires, which I feel is very odd for something with 4 wheel drums...

 

I've also found out that If I get the drums soaked with water from the rain, as soon as they dry out down the hill I have more stopping power, and can lock up the tires a ton. 


Normally I'd chock this up to shoe contamination, but there's no leaking fluid from the brand new wheel cylinders, and the shoes are brand new with little dust contamination. Even with brand new, freshly adjusted shoes and perfectly clean brake parts, it didn't brake as well as I feel it should have.

[Str8_69]

Maybe it's just shit brake material. Who knows what they use to line those shoes? Prolly horse meat.

[datzenmike]

MM hows the front alignment?

 

 

I may have got it wrong... but the leading shoe is any shoe that is towards the front of the vehicle. The leading shoe has the brake material farthest from the wheel cylinder. Try that.