I have a 2004 Nissan Frontier with V6 non-supercharged engine, 4x4, with manual transmission, 150k miles. For approximately the last 30k miles, I have had a persistent shuddering in the cab when I apply the brakes slowing from about 15 to 0 MPH. It is accompanied by a low humming noise that decreases in pitch as the truck slows down. It only happens when the brakes are warm; about 70+ degrees outside or after I’ve been slowing down a lot. It does not seem to correspond to engine temperature, only my perceived temperature of the brakes. There is no pedal feedback, and it does not shudder when I stop using only the parking brake. It does not seem to affect stopping distance.
I first tried to fix it by doing a very thorough front/rear brake job - new pads/shoes, new rotors/drums, and repacked front wheel bearings. That had no effect on the problem. I tried rotating the tires and that had no effect. I then did a complete front end job and replaced all the bushings and balljoints via brand new pre-assembled control arm assemblies. I also replaced the tie rod assemblies, sway bar bushings/end links, and had an alignment done. That had no effect.
Based on the repairs I’ve done, I would assume that it is having to do with the front brakes, but is not warped rotors or anything in the front suspension. Anyone have any ideas?
Its probably just some deposits that build up on the rotors from the resins used in the brake pads. I find that this goes away, for awhile at least, by doing a couple of hard slowdowns from 60-65 mph. Don’t lock up the brakes, but just short of that so you use the brake pads to scrub the rotors clean. Don’t come to a complete stop, just slow to about 5-10 mph and then accelerate again.
The build-ups that keith mentioned can certainly be a possibility. Cheap/low end brake pads can make this a chronic kind of issue.
But you also weren’t clear about what happened after doing the brakes. Did the shudder stay the same even with new pads/rotors? If so, then the rotor build up isn’t the most likely possibility since the new stuff should have kept it quiet for a while.
Here are a couple of things, though I’m not sure about the set up on this vehicle - one is lug not torque. If the lugs are not torqued properly and evenly each time the wheels go on it can create these kinds of problems. The other issue to think about is the hub surfaces where the rotors mount. You could put brand new rotors onto an old hub and remain with the same “warp-like” issue. Even very tiny buildups of rust or other crud can keep the rotor from seating properly on the hub.
Although you do say that there is no pedal feedback which makes those issues suspect. Did you ever replace the flexible brake lines in the front? The interiors of those can break down over time & mess with fluid flow. I could imagine a case where something about those created some kind of uneven pulsing brake action. Maybe a stretch, but the things you’ve done normally cure these issues.
Another oft overlooked item is the SLIDERS… Your front calipers usually have a greased shaft that the caliper actually slides on…many X these sliders get really gummy from the original grease getting dried out or cooked by brake heat. When this occurs the caliper does’nt actually grip the rotor squarely…this can cause chatter and or brake pad dragging…noises…the whole gamut of undesirable brake characteristics really. See if you have those slide pins and if you do clean and grease them so they operate properly… ALL my Hondas had them, not sure about the Frontier tho…
Does this truck not have sealed wheel bearing/hub assemblies? Just how did you repack the front wheel bearings?
My gut feeling is that the hub nut is not tight or more than likely, the wheel hub bearing is worn and this is the cause of your brake shudder.
Odd tire wear patterns can cause a humming and even a strange sensation in the brakes in some cases but I’d still like to hear a bit about the wheel bearings.
Thanks for all the feedback! I’ll try to address all the questions:
Keith - I get out of the city pretty often (I live in CO) so I have already had some opportunity to brake hard coming down the mtn passes. The rotors were cleaned thoroughly with brake cleaner after I did the front end work as well.
cigroller - As I recall, I purchased middle/high quality brake components from Napa when I did the brake job, but I was having this problem before and immediately after I did the brake job. The new parts seemed to have no effect. I do own a torque wrench and torque each lug to spec (and in the crisscross order) after removing the wheels. I’m pretty sure I completely cleaned all the parts with brake cleaner and a brush before reassembly. I did not replace the brake lines, so this may be my next move.
Honda Blackbird - The calipers do have the sliding pins and I inspected the action during the brake job. They seemed to move smoothly and freely. I did not regrease them, so this is another possible culprit.
ok4450 - My truck has the roller style angular contact bearings. Definitely not sealed. I pulled the auto lock 4x4 hub, removed a bearing preload nut, and had access to both inner and outer bearings. Cleaned everything out thoroughly, inspected and repacked each bearing individually, and then packed in a bunch more grease after installing the bearings. Aside from the shudder, the truck rolls silently - I imagine I’d hear something suspicious if one of the bearings was shot. Tire wear is normal and have not seen anything unexpected. As for the preload nut, I marked the position so I could clock it to the original position during reassembly. Since it shuddered before I pulled the rotors, it would have had to have been a faulty installation from the factory.
Thanks again for all the feedback. I think I’ll try replacing the flexible brake lines, completely flushing and filling the brake fluid, greasing the caliper slider pins, double checking bearing preload, and cleaning the hub mounting surfaces next. I’ll let you know what I find out.
You might want to revisit the front bearing nut adjustment. They adjust them properly at the factory but over time the preload will change due to bearing and race wear. The bearings may be perfectly quiet in this condition too.
The general rule of thumb is to rotate the wheel by hand as you snug the bearing nut up somewhat tightly. The nut is then loosened a round and then (while still rotating the wheel by hand) snug the nut up just until any looseness is gone.
Before doing this you might grasp each front wheel at the 3 and 9 o-clock positions and determine if there is any movement in there at all. It only takes a few thousandths of an inch to cause a brake shudder.
OK4450, he has 4wd so its not that easy. It requires a ft/lb torque wrench, an in/lb torque wrench, a special tool, a fish scale and a complex procedure. I hope the OP has either the factory service manual, access to alldata or maybe a Chiltons or Haynes, but I’m not sure the latter have the procedure.
Yep…OK4450…4x4 trucks usually have the old style re-packable front bearings with the center nut…or at least my 91’ Explorer does…and the few other 4x4 Ford trucks I have wrenched on. I don’t think I have ever seen a sealed bearing 4x4 front setup before… I thought it had to do with the way the front hubs are setup…Anyway I guess they could presently use the more modern sealed bearing style these days…Ive just never seen them yet.
Also sometimes those slider pins get bent along the way somehow…they sell replacements in the brake HW kits they sell…so no big deal if you find a bent one. Not sure this is the issue…just something to check I guess
*** As for a manual for procedures…Auto Zone has FREE online Service manuals to look at for almost every make and model…its a pretty nice resource and keeps my bookshelf from collapsing LOL
I understand the inch/pounds and fish scale thing (I own both of those) but also consider them a bit irrelevant on a 150k miles set of wheel bearings.
When that truck was new on the assembly line you can bet your bottom dollar that Nissan did not have anyone using an inch/pounds torque wrench and a fish scale on those bearings when they were new. No doubt it was an automated wham, bam, done machine.
Even if one used a fish scale and set the pull to say 7 pounds (assuming the scale is even accurate) the pull is going to be different as mileage accrues.
If the factory set the pull at 7 about 150k miles ago the odds of the pull being anywhere near 7 now or in the last 90k miles is probably hovering around slim and none.
I’m not advocating slopping something together, just pointing out that there’s a lot of leeway on a ho-hum production line vehicle. The same theory is applied to front end alignment specs as an example. If the preferred camber setting on a vehicle is '30+ it should not be assumed that all vehicles off the assembly line will be at '30+. They won’t; some will be 0, some 1 degree +, some '45+, and various other settings in that general range.
It only takes a minute to determine wheel shake and the point about sticking sliders is a good one. This could be especially true if the truck is in an area with a lot of road salt, water, etc.