So I changed the drums, shoes and hardware yesterday and now I’m getting a pulsation in pedal only when braking. A bit more prominent at 25-40mph than at highway speeds. I put on bendix drums and shoes with new springs. Passenger side cylinder also replaced.

Does it need to break in or something? Maybe a coating on the drum? I did spray it out with brake cleaner.

Are you supposed to have new drums machined before it’s installed? Because I put another set on and I’m getting the same problem.

A1218 wrote: ↑

Fri Aug 19, 2022 10:01 am

Are you supposed to have new drums machined before it’s installed? Because I put another set on and I’m getting the same problem.

No, they're supposed to be machined correctly from the factory, just like rotors.

VStar650CL wrote: ↑

Fri Aug 19, 2022 12:34 pm

A1218 wrote: ↑

Fri Aug 19, 2022 10:01 am

Are you supposed to have new drums machined before it’s installed? Because I put another set on and I’m getting the same problem.

No, they're supposed to be machined correctly from the factory, just like rotors.

What’s the likelihood a few set of drums are warped from factory? Is this normal until it breaks in or is it the pads? I don’t think it would be.

A1218 wrote: ↑

Fri Aug 19, 2022 1:26 pm

What’s the likelihood a few set of drums are warped from factory? Is this normal until it breaks in or is it the pads? I don’t think it would be.

It's not normal, and the likelihood is pretty small unless they're the same brand and bought from the same store. Then it could be a bad manufacturing batch or damaged in transport. I'd take them to the nearest parts store that has a lathe, have them jig the drums up and measure the runout (or record it during the cut).

Yep. Not normal, yet I had the same issue once in my life on a set rear drums I purchased from a auto parts store. Took them back for an exchange with another set of the same make and had the same problem. Got those refunded and bought another brand with no issue. The best I was able to make out regarding the cause was not warpage but instead a lack of precision with respect to the lug bolt hole pattern not being concentric well enough with the machined ID of the drum.

mdmellott wrote: ↑

Fri Aug 19, 2022 6:46 pm

Yep. Not normal, yet I had the same issue once in my life on a set rear drums I purchased from a auto parts store. Took them back for an exchange with another set of the same make and had the same problem. Got those refunded and bought another brand with no issue. The best I was able to make out regarding the cause was not warpage but instead a lack of precision with respect to the lug bolt hole pattern not being concentric well enough with the machined ID of the drum.

Do you recall the brand you went with in the end or was this not on your Pathfinder?

So you believe it has more to do with the lug holes than the drum itself being out of round? I got another set of replacement from the auto parts store and I may have them machined first to see.

A1218 wrote: ↑

Fri Aug 19, 2022 9:26 pm

Do you recall the brand you went with in the end or was this not on your Pathfinder?

So you believe it has more to do with the lug holes than the drum itself being out of round?

Yeah. This was before my Pathfinder was born. Early to mid '90s for my dearly departed '89 Mustang. I don't even recall what store it was, much less the brands I bought.

The ID was measured with a caliper at multiple positions and found to be perfectly round. Measuring the precise concentric orientation of the bolt circle with the ID of the drum was harder to do with the limited tools I had at the time but that is what I suspected to be the issue given the questionable measurements I was able to make.

The hub locates the drum, not the lugs, there's way too much play there and with 6 lugs you'd never get the suckers off in the rust belt if they were what located them.

Now that's not saying they couldn't have been machined off center, just that the lugs aren't the determining point.

OP. If your pedal shudders with new drums and you didn't do anything to the fronts, the new drums are bad. One or both.

Mike W. wrote: ↑

Fri Aug 19, 2022 10:58 pm

The hub locates the drum, not the lugs, there's way too much play there and with 6 lugs you'd never get the suckers off in the rust belt if they were what located them.

Now that's not saying they couldn't have been machined off center, just that the lugs aren't the determining point.

It's actually both. The hole for the hub locates the drum diametrically, but if the stud holes are off from it then the drum will fit the studs but not seat on the hub. The entire pattern must be correct and centered, and the stud holes can't be much sloppier than the hub hole or they'll allow the drum to "walk" around the hub under high torque loads.

Looks like there’s several places for an error to occur. I have one more set of replacements I’m trying today and if that doesn’t work out I’m throwing my original ones back on. It’s kinda ridiculous to pay almost $200 for new drums to have to spend another 50-80 bucks to have them turned when you shouldn’t have to. And I’ve tried so many already.

Well I changed the drums again this evening with a set of replacements, but this time I decided to change the shoes out so I picked up a set from Autozone for the heck of it and I took the Powerstop ones off that I put on last week.

I’m keeping my fingers crossed as I am reporting no vibration or pulsation in vehicle or pedal. I took it on the highway up to 55mph and did a steady but not aggressive braking yet, and I did not get any issues. City driving, nothing felt. I did notice the powerstop shoes were noticeably thicker than the Autozone and Bendix shoes. I even had to expand the adjusting rod several threads for it to start touching the drums with the bendix or Autozone shoes, but with the Powerstop, I had to dial it all the way down just to get any drum on.

Hmm. sounds like you just had the wrong shoes. Think about the way the shoes operate. They don't expand out uniformly, only at the top and their position is fixed at the bottom. So ill-fitting shoes will scuff at the top and make no contact at all at the bottom. That lets them rock, hence vibration. It didn't occur to me till now that maybe the shoes were the wrong part and not the drums.

Oh do the issues continue. Now that the vibration and pulsation issue has been solved I seem to be encountering another issue. The passenger side drum is getting significantly hotter than the driver side. You can put your hand on the driver side for over 4 seconds but definitely not the passenger side. When I installed the drums, I tightened up the star adjusters just enough to allow the drum to slide on and off without it being wobbly and loose. I know the self adjuster tightens it up when you pull the handbrake and I did notice the handbrake get tighter since Sunday, but it’s still within the spec of 6-8 clicks as I get 6 clicks. I did get a set of replacement star adjusters off another Pathfinder as the teeth on mine were a bit shredded. Each side has a different thread direction and I placed them correctly along with lubing and ensuring they were properly working.

The drums were equally warm to hot but not scalding the first two days. Why is the passenger side getting scalding hot?

It's more likely that the side opposite the hot drum is loose rather than the hot drum being tight, but it could be either one. Pick up the rear and see if the side getting hot spins freely, if so then the problem is the opposite side not doing enough work.

How hot should drum brakes get under normal driving circumstances?

Not too hot to touch unless they're working very hard, and there certainly shouldn't be a huge temp differential across the axle like that.

I raised the rear and the driver side was spinning by hand but with a light drag so that was fine. The same passenger side that was hot was tight. I slacked it off until it spins with a light drag. It wasn’t that tight when I put on the drum a few days ago.

Sounds like the adjuster isn't working right, then.

So I checked with an infrared thermometer after some highway and city driving. The driver side drum is coming in around 130 degrees at the face of the drum and the side where the pads would touch on the inside of the drum are around 140-143 degrees.


The passenger side is 134-139 degrees at face and around 148 at the side. So they’re not far off really.

In terms of braking heat, that's negligible.