How to: K2500 front rotor / disc replacement - 8 lug, 4x4

[Steve93mustanglx]

Did this today. Wow what a difference with non-warped rotors! I recommend a brass hammer on the studs. Most came out with a single good whack. The 4 15mm bolts must be removed before whacking on old rotor and hub assembly. Otherwise, it ain't moving. I beat the hell out of the drivers side rotor and hub assy with 4-5 pound hammer to get it removed from the axle. It didn't want to play nice.

Not sure if previously mentioned, but be sure to tighten those 15 mm bolts evenly so as not to cock the hub/rotor assembly as it goes back together. Also recommend putting axle nut on loosely to keep rotor/hub assy front falling off. It is quiet heavy and your foot is gonna probably be under it.

This job wasn't nearly as bad as I feared, but still solidifies my belief that it is not surprise GM went bankrupt. Yes it works, yes I love my sub, but honestly, a dumb design.

 

[Jeph]

Hi, I am about to change the rotors out and was wondering if anyone could give me the spec on the hub bolts? I read somewhere else they are an M14x1.5, but do not know of this is true. Length and grade would be appreciated if available. Thanks Jeph

 

[K2500_1TON]

thank you for this info. i was attempting to pull off the rotor today with no luck. but i will try next weekend using the info you provided. this helps a ton. that chelton book is currently on the bbq.

 

[pemmink]

I would like to add my thanks to the author of this thread and add a few "helpful hints" that I discovered when changing rotors this past week.

The 4 bolts that hold the hub to the knuckle ARE a bitch! I found that a 9/16 socket worked nicely as it is slightly smaller than the correct 15mm and my bolts were very rusty, making the heads a bit smaller. All the bolts came out (eventually) intact, however pounding on them to break the hub loose destroyed a few.
These bolts are EXPENSIVE (in Canada), about $10 each.

Someone mentioned repacking the hubs. I think this can be done through the hole where the ABS sensor mounts, however, you will probably break the sensor trying to remove it. Sensors are around $170 here. My ABS was already disconnected so I tried very carefully to remove the sensors - broke both of them.

Someone mentioned the trick of using an old rotor under the hub/rotor assembly. This works really well when pounding the studs back in.

Thanks again for the thread, I couldn't have done it without you guys.

 

[coachjpg]

I'm preparing to replace my '99 C3500 front brakes and rotors. I called the dealer's parts folks, and their disks come with a new hub attached. Evidently GM doesn't expect their mechanics to separate the disk from the hub.

 

[whatnot]

2 wheel drive is different.

 

[jack it high]

I dont know if this has been discussed but im working on the brake rotor on my 89 chevy k2500 i saw a couple post on here where it shows taking bolts out and removing the hole hub assembly but say if some one got a lil mad and just started beating on the rotor and managed to remove part of the wheel hub well split it more like how could they fix it lol please ppl take it easy on me. im a small engine mechanic not a auto mechanic

 

[whatnot]

If the hub came apart you need to replace it.

 

[Sharm]

Yes line splines up and hammer in as said in the 1st post. Bearings are sealed but you can add grease from what I have read. Not sure how.

The 4 bolts holding the hub/rotor on are the worst part of the job for some.

I have repacked sealed bearings on machinery at work. You can pop out the seal and then repack. But you dont want too much grease repacked for it can cause them to over heat. I have seen some sealed bearings with very little to almost no grease. You take a chance but popping the seal out that it may not stay in when you go to pop the seal back in.

 

[hereismylife]

I have repacked sealed bearings on machinery at work. You can pop out the seal and then repack. But you dont want too much grease repacked for it can cause them to over heat. I have seen some sealed bearings with very little to almost no grease. You take a chance but popping the seal out that it may not stay in when you go to pop the seal back in.

I heard this before when having to much grease. Why don't bearings overheat when using a buddy bearing. Just curious....

 

[Sharm]

I M NOT SURE EITHER. i HAVE SEEN THEM USED ON EQIUIPMENT. THEY SUPPY A SLOW STEADY SUPPLY OF GREASE. iT MAY BE THE GREASE THAT IS USED.

 

[wolfman102001]

I tried to do what you said, but the rotor still didn't come off....Is there anything else you can tell me to do??? I even tried to pound them off with a 4lb sledge and it wouldn't budge.

 

[3500GMC]

The entire hub and rotor must come off- CV axle nut must come off as well as the 4 bolts that hold the hub to the knuckle. THEN you pound or press out the studs. This will then free the rotor from the hub. Study the pics. New hubs come with new studs, new rotors do NOT. Use a brass or aluminum DRIFT to drive out the studs so you don't F up the threads.. Even then there's no guarantee.

 

[wolfman102001]

My problem is the rotors, after I removed the 4 bolts, won't come off the truck yet. I didn't know if there was something I was missing still as to why it won't slip off the main hub???

 

[3500GMC]

With axle nut and caliper off, the hub will need some PB blaster and some 'persuasion'...

You see, the rotor is held to the hub with the studs. Both must come OFF first. Knuckle is where the ball joint attach to. Hub is the four bolt flange (at knuckle) and 8 bolt flange (at wheel)...

 

[ak diesel driver]

the hub has a tendency to rust into the steering knuckle. first time off can be a real pain. de rust everything and use antisieze when going back together and then next time is easy

 

[jrsavoie]

You can try threading the bolts back almost all the way and wacking on the bolt heads. I would have new bolts on hand before you do though. I pulled my bearing apart by wacking on the rotor. Ended up making the job just a little more expensive.

 

[Sharm]

I am about to do the same job. I have not got to doing the job yet since I find out that you need to replace the spindle nuts after you take them off. Thats fine and all but the local auto supply do not stock them on shelves. So you have to order them. I am looking at using a puller to put pressure on the rotor then tap on the hub. I have used this method on equipment at work and it does well. Once I get my spindle nut I will set up to do the job. PLus I have a bearing press I can use for pressing out the studs and also pressing in the new ones. I really hope I dont have any surprises. Anti seiz with definately go on the parts as it goes back together.

 

[Sharm]

Ok, job of replacing rotors was not as bad as I had invisioned it. I have a bearing press and bearing puller. After taking off the spindle nut. I used the bearing puller to push the spindle back into the hub a little. Basically I was just started the moving process of the spinde from the hub. I had sprayed the 4 bolts on the hub with PB blaster and let set for awhile. Using a 6 point 15 ml socket on a torque wrench I applied pressure slowly to the bolt and they came out with out any problem. using a pry bar from behind the rotor I applied pressure at different points to start the hub separation. also tapping the rotor a little at a time. Don't try to move it all at once with one blow. Using a brake adjuster for rear brakes works great for getting into the space of the hub to help move it along better. After I got the assembly off I used my bearing press to pop out the studs. One assemble the studs came out hard and the other side fairly easy. After the studs are out. Use the hub bolts by putting them back into the hub about 1/4 inch is all thats needed. turn upside down and pop on the rotor to separate the rotor from hub. Put new rotor on hub slip studs into holes and use a shaft or long bolt about 6 inch, to tap the heads of the studs in. dont worry about getting them all the way in at that point. Putting the rotor and hub assembly was another issue. I did clean up both areas and greased up the cavity area. I had experienced the spindle wanting to slide back while trying to push the assembly back on. I applied a pair of vise grips on the shaft just after the rubber boot and against the frame area around it. You will see what I mean shortly after trying to put it on once and the spindle keeps sliding back. The vise grips help it from sliding back while your trying to put the hub back on the spindle. I am sure anyone doing the job of replacing the rotors will have your own problems. I was fortunate that someone down the road before me on the truck had anti seized the bolts before. Unfortunately I had to buy the socket for the spindle nut because I didnt own a 36 mm socket. Well now I do. The size of the nut that came off was a35 mm but the new nut (which is recommended each time they come off) was a 36. I would say if you come across that too. get the 36mm 6 point socket. It will be close enough to the 35 it wont slip. Good luck

 

[peerless1]

so i know this an old post but its the only thing on the web that i can find to do the brake job. the drivers side 15mm hub came off pretty easy, but on the passenger side is being more difficult and one of the 15mm bolts stripped and rounded off, so now im thinking im screwed, any one have any ideas and getting it loose and out so i can replace it?