[enigma]

'01 V6 3.2L 4wd Rodeo.
Drive slow and hit the brakes normally - they feel fine. Drive fast (50+ mph) and hit the brakes to come to a complete stop and I feel like I've got a hard pulsing against my foot (through the brake pedal). -So, its gotta be brake or wheel related in some form (brakes, rotors, hubs, beerings, etc). I only slightly feel the pulsing in the steering wheel - so I don't think its anything with the rack / suspension (I've driven other vehicles with a blown rack and fairly destroyed suspension before and it was a much more pronounced vibration / forced shifting of the steering wheel).

Does that logic sound right? This is likely a brake / wheel issue?

Problem just started about 2 or 3 weeks ago. It has gradually gotten worse.

Now, I installed Superwinch manual hubs about three months ago and replaced the bearings at the same time. I was certain at the time that I got the bearing nuts installed tight enough. I have double checked the lug nuts - they're tight. When installing the hubs, I broke the tip of a torx bit off in one of the little bolt heads. I also overtightened two other bolts. (these problems were only with one side, the other side was / is fine.) After trying many things, I had to have my mechanic pull these three bolts - this was about 3 weeks ago. I don't know what exactly he did when he did this but it seems that he used a pry bar on the back side of the silver Superwinch hub cap where it meets the black 'backing' metal part because is (the silver piece) is now cracked in that area in a wide C shape that seems to be the length of a pry bar - this is on two different sides of the silver cap. This doesn't extend very far into the silver cap piece though.

The replacement of the three bolts and removal of the Superwinch silver cap piece using (likely) a pry bar is the only change that been done to the front end in a long while. Mechanic replaced the bolts with others I bought from Superwinch and reinstalled the same silver cap piece.

I thought something easy to check would be the ABS system malfunctioning. I pulled the ABS fuse and drove for a while - no change. I don't think ABS is the issue. (The fuse is back in at this point)

No, I don't have the manual hubs locked in the 4wd position and yes, I've tested, the hubs lock and unlock without problem.

The truck is up 3.5inches with a Basic Lift kit from Indy4x.

Any thoughts? What might cause these symptoms?

I'm thinking the cracks in the silver hub cap piece has allowed water in causing the grease to wash out.
Or, my rotors are warped (I haven't hit anything though so I don't know why they'd suddenly be warped).
Or, I've got an issue with the master cylinder (don't know much about brake lines and the master cylinder).
Or, I've got air in the lines.

I'm not sure. I'd appreciate any help or pointers of where to start looking. I don't want to put this into a shop but theres only so much I can do at this point (medical issue causing more trouble). I can certainly jack it up and pull apart the hub and check there and the outer part of the bearing if you think thats best.

???

Thank yall! Sorry for the long post.

 

[SurferJoe]

Check run-out in the rotors and/or drums.

I've seen thin pads cause this too - I never let my pads get below the thickness of the backing material.

 

[CatFuzz]

Grease on the rotors from your recent work could cause the pulsing. The grease causes a hot spot to form. Pull the rotors and have them re-surfaced.

 

[FossZ]

its front rotors for sure. the fact that you feel it in the steering wheel and not in the seat rules out the rear. if your bearings were devoid of grease, they would growl like a dragon going down the road

 

[SurferJoe]

Naturally you've confirmed that the lugs are tight - right?

Anyway - it's never a good idea to machine the rotors as you might do to correct any run-out, and remove the wobble of the rotor that was caused by heat.

Once you cut the rotor thinner, it's ability to withstand heat is diminished and you're back into a wobbling rotor again a lot sooner.

FWIW: I never machine the rotors on anything I own - ever. If they are bad enough to need machining, I just replace them with new ones and get it over with.

And about the friction material getting to the thickness of the backing - well, that's just me - but again it's a heat-sink situation and when they get to about the 50% wear point, they cannot take the heat and radiate it away by themselves, so the rotors get overheated.

Heat's the enemy here and anything one can do to minimize it is all for the good.

 

[enigma]

Check run-out in the rotors.

Hey, thank you all for the responses! Sorry I didn't respond - a lot going on...

Yes, the lugs are tight.

"Check run-out in the rotors"... if I replace the rotors, will this be a moot point? Does run-out apply to the rotors specifically or is it caused by another component?

I stopped quick today and picked up front disks and pads. The disks were apparently resurfaced years ago by the previous owner. I'll be replacing these this weekend and will also be inspecting the job the mechanic did on the one manual hub. Hopefully it will not go back to being an auto hub.

I appreciate the help from you all!

 

[SurferJoe]

Replacing the rotors should do it as they are prolly flat from the manufacturer.

As I can tell in over 50 years of auto repair work, the need to machine a new rotor was very overrated and only once did I see one that needed to be trued up out of the box.

The old wive's tale of every rotor needing to be machined 'cause they get bent when they are shipped never proved correct to me.

Just be very sure to remove and rust and crappola on the surfaces where the rotor meets the hub to provide the best concentricity and least run-out.

 

[enigma]

Thanks SurferJoe! I will do that - clean rust from the backside of the hub piece where it meets the rotor.

Two more things:
1. What is "run-out"?
2. I've looked into this in a few different ways now but I haven't actually found a detailed picture of this... It seems that the hub piece is bolted to the rotor with six bolts. Is this true? The lug nut studs- Do these go through the rotor AND hub OR just the hub? (looks like its just the hub per posts on this site and the MyIsuzuParts.com site) Basically, I'm asking if I'll need to address the lug nut studs at all (they're in fine condition) AND if there is anything other than the six bolts that attach the hub piece to the rotor?

Thanks again!

 

[SurferJoe]

I forget about the studs on the front of the 4WD hubs - but you likely had to hammer them out and re-insert new ones if I remember correctly.

That's the way it is on most vehicles. No biggie though.

A 32 oz BPH and a couple of heavy drifts or spider cross shafts and they are done.

You do NOT need to upset the studs to lock them, although that's a good thing to do. Not totally necessary though.

RUNOUT = ever have a record that wobbled? That's runout.

 

[enigma]

Runout... gotcha. Thanks

With the lug nut studs- You confirm these are attached to the hub. Do you mean only the hub? Are they attached to the rotor at all? If I remove the six bolts holding the hub to the rotor and separate the two parts without even touching the lug nut studs, will they remain with the hub?

(Just trying to determine if, to save time and effort, I should just purchase new lug nut studs and drive them into the new rotors ahead of time)

Thanks

 

[SurferJoe]

Somebody's gonna have to help here as I don't know if the rotors are floating on the 4WD hubs or not. They certainly aren't on the 2WD versions and the factory upsets the shank of the studs to lock them onto the rotors as they pass through them.

That is the way it is on my '89 Amigo anyway and it has been an industry standard for prolly 50% of all vehicles made AFAIK.

When I say 'upset' - I mean that there is a special swagging tool that deforms part of either the rotor or the stud itself to kin of 'rivet' the stud to the rotor. And like I said not all manufacturers perform this function.

One can install studs with a hammer - yup.

 

[Dae]

To remove the rotor, you have to remove the hubs because its bolted onto it.
Removing the hub also requires you to remove the wheel bearings. The studs do not go through the rotor.

This is what you're going to be messing with.
http://planetisuzoo.com/articles.htm?id=56&Isuzu_Front_Bearing_Repack

Once you remove the bearing locking nut. You can remove the 6 hub to rotor bolts. And it comes right off. Might need to tap it with a mallet.

These two threads are also very helpful.
http://forum.planetisuzoo.com/viewtopic.php?t=42686
http://forum.planetisuzoo.com/viewtopic.php?t=42928

 

[enigma]

Excellent! Thanks guys!

Yes, it is just the lug nut studs that were kinda a mystery to me. I did previously look at the links you pointed out Dae and I apparently missed the one picture of the hub (apart from the rotor) with the studs installed in it (the picture next to the AutoZone brake cleaner)! That picture is exactly what I was looking for.

Thanks again! I'll let yall know the results from this weekend (assuming it doesn't rain).

 

[vanduker]

What I've seen on my Troopers (same brakes) is hot spotting. I do a volunteer gig where I drive fairly fast and brake fairly hard and then park the vehicle. What happens is most of the rotor cools but the part that ends up covered by the pad does not. This causes part of the pad material to cool onto and into the rotor. Makes a spot where the friction is different from the rest of the rotor so even if the surface is even (no runout and no "warping") the pedal still pulses and only gets worse over time.

Like SJ says I stopped having rotors surfaced as they are cheap to buy and I don't trust people to resurface them properly, at least not anyone who I trust that is cheaper than just replacing the disks.

http://www.stoptech.com/tech_info/wp_wa ... disk.shtml

 

[enigma]

Hey all! Yesterday, I replaced the rotors and pads, repacked the bearings (just did this not too long ago) and checked over my damaged (on the outside only) superwinch hubs.... Everything is back together and the pulsing against my foot is gone.

Job took two hours longer than it should have thanks to PepBoys selling me the wrong pads and one disk with a bolt hole that wasn't threaded. (This - wrong pads - has happened before with another vehicle and I apparently didn't learn my lesson)

Anyway, thanks to all of you who helped out!