Front brake upgrade question

[Tx Surveyor]

Hey Everyone,

First post but I need some advice. I have an '85 K5 with a 305/700R4/208. I am having front brake issues, so I want to replace my front brakes but I figure while I am at it I had might as well do some sort of upgrade. Also while I am replace rotors I might as well throw in some locking hubs.

I'm looking to do this on a some what of a budget since I'm broke anyways. What sort of kits have some of you had luck with when it comes to replacing pads and rotors? What about locking hubs?

Thanks,
Surveyor

 

[dremu]

For the locking hubs, IMO, there is one option: Warn Premiums. (Well, I gather the OE Spicer ones were slicker, but unless you find a set NOS or at a dealer ...) The auto hubs fail when you need them most, so they're crap. I rate the other manual hubs (Warn Standard, Milemarker, Superwinch) all about the same, one step down from the Premiums.

Rather than buying new fancy ones, I'd take your rotors -- yes, Scott, with the hubs attached* -- to your local auto machine shop; they can tell you if there's enough meat to turn them. If so, have them do it and call it good. If not, then get a brand name set of stock replacement rotors.

(* Scott "4x4HIGH", our resident auto machinist insists that the only way to really true a rotor is to turn it while it's mounted to the hub. The purist will actually turn brand new rotors, so that they're true to those particular hubs.)

For pads, I'm partial to the Bendix 'cuz it's what my local place has, but any brand name semi-metallic should do fine -- I've had good luck with the Raybestos too, IIRC. Organics suck, and IMO, ceramic is over-rated. They don't work for squat when cold, so your first coupla stops out of the driveway in the morning can be exciting

Honestly, I'm leery of brake "upgrades." Your brake system is a just that, a system, and changing one component can throw the whole system off. (Note that both my trucks have rear disc, but some of that is that I hate drums.)

I bought a M1009 CUCV a coupla years ago, basically a military version of your truck. The brakes were so bad I was puckered to the seat driving that thing home.

I replaced the master cylinder, the calipers and wheel cylinders, and I think all three brake hoses, and then of course flushed and bled the living crap out of it. After that, with stock parts, that thing would stop on a dime and give you change. Slamming on the brakes at speed was fun; it'd lock all four and slide, and that was on fresh 33"x12.5" AT's

Anyway, point being that stock parts can do just fine... no need to blow $$ on exotic stuff when you can get what you need for less from the parts house around the corner.

-- A

 

[badmix]

Good replies.

NOt much to add, except if you had the money to upgrade to SS brake lines. Get ones a couple inches longer incase you lift your truck later on.

 

[dremu]

Good replies.

NOt much to add, except if you had the money to upgrade to SS brake lines. Get ones a couple inches longer incase you lift your truck later on.

Oh yeah ... just to be clear, they're steel *braided* lines, still rubber inside, but the braid keeps them from swelling so much, and protects them from abuse, if not the elements. And yeah, if you're ever thinking you might do a 2-4" lift, that's one place I can justify blowing a little extra $$.

-- A

 

[Tx Surveyor]

Thanks for the advice. I think I priced it all with new locking hubs and it came in around $350. That's for stocker parts.
Getting my old rotors turned won't be an option, I have .03 deep grooves that are .05 wide.
Anything I should look out for when I install the new hubs? I've never done it before.


Thanks,
Surveyor

 

[dremu]

Read up on the magic locking nut (I know, highly technical term... )

You'll need an axle hub socket, which is a fancy name for a $15 socket with four tangs.

http://cgi.ebay.com/ebaymotors/Perf...emQQimsxZ20090212?IMSfp=TL0902121210008r26036

Kragen (Checker, Schuck's, O'Reilly) used to carry them, but I couldn't find it on their web page just now. Napa would prolly have the OTC 7270.

There's a complicated process to R&R the nuts (two each side) and their locking mechanism, and torquing the thing is a bit goofy. Make sure you have your Chilton's handy.

-- A

 

[nchinca]

A couple things you might consider are 3/4 tom HD front calipers with huge pistons, I believe they are physically the same size (I could be wrong) and maybe consider stepping up to hydroboost. Without upgrading axles, you are pretty limited. Even upgrading the axles, there is not much aftermarket, except they are bigger brakes from the factory. Now though you are looking at more money - it is a circle.

 

[dremu]

A couple things you might consider are 3/4 tom HD front calipers with huge pistons, I believe they are physically the same size (I could be wrong) and maybe consider stepping up to hydroboost. Without upgrading axles, you are pretty limited. Even upgrading the axles, there is not much aftermarket, except they are bigger brakes from the factory. Now though you are looking at more money - it is a circle.

Yeah, the 3/4 ton calipers are physically the same size. Whether the larger piston is better or not degenerates into a nerd argument (same force spread over a larger area is less pressure per area, etc etc.)

Hydroboost IS great ... but it means a new master, booster and brake pedal. BTDT

-- A

 

[swartlkk]

Not to perpetuate a "nerd argument" as you have called it, but please do correct me if I am wrong... The master cylinder provides pressure, not force directly. Same pressure spread over a larger area == more force. That is if that the master cylinder has the stroke necessary to provide the additional fluid volume to pressurize the piston. Since people have done this swap, it would suffice to say that the stock MC has enough stroke to fully pressurize the larger piston.

And I would agree on the brake force. The brakes on my 74 K5 are excellent and I have not touched them!

 

[Tx Surveyor]

Where am I going to find the best deal on Warn premium hubs?



S

 

[4X4HIGH]

Even if you are buying NEW rotors make sure to have them installed onto the wheel hub and then have them machined true to that hub. I know that people here are going to argue this point with me but i do this professionally (for the last 22 years) and you MUST machine the rotors after they are attached to the hubs since the hub is what makes the rotor run true. You cannot machine a rotor on either a fixture or another hub and expect it to be true once it is removed and installed on a different center (different hub).

As far as any available upgrades are concerned there are always drilled and or slotted rotors available. In most situations they are not needed unless this vehicle is always pulling lots of weight and doesn't want to stop very easily. If that is the case then a drilled/slotted rotor and even the ceramic pads would be a good upgrade. Just remember though as Aaron said the ceramic pads do not stop good unless they are nice and hot.

If this were my rig i would just replace with all factory parts and make sure the rest of the brake system is in proper working order and you should be fine.

 

[Big Blzn]

Scott, I thought that I read or heard somewhere that the drilled and/or slotted rotors were unnecessary on anythig other than a high performance sports car or true race car.

 

[4X4HIGH]

Scott, I thought that I read or heard somewhere that the drilled and/or slotted rotors were unnecessary on anythig other than a high performance sports car or true race car.

That is not true. The drilled and or slotted rotors come into play on any vehicle that is hard to stop because of brake fade caused by extreme heat. The drilled/slotted rotors help to remove gases that form between the rotor and pad and also to help move more air which means the removal of heat. Many people do use them in cases where they aren't needed and are there for nothing more than bragging rights. Let me also state that while the drilled and or slotted rotors will help braking in the vehicles that truely need the extra help will also go through brake pads much quicker.

 

[blazin_blazer]

4x4high, i'm confused...the rotor needs to be put on your hub w/lugbolts pressed in place so the rotor is turned correctly? will the rotor lathe turn the rotors w/hub in place? does it mount the hub & rotor w/ the bearings, just like its bolted to the spindle? if rotor is turned w/o the hub & both sides are parallel, what difference would being mounted to hub make. i'm not doubting you, just trying to understand. also, should you do the same when you do rear disks? after you press the 3/4 ton hubs on the rear hub, should they be turned down to have them parallel w/14bff hubs?

 

[dremu]

4x4high, i'm confused...the rotor needs to be put on your hub w/lugbolts pressed in place so the rotor is turned correctly? will the rotor lathe turn the rotors w/hub in place? does it mount the hub & rotor w/ the bearings, just like its bolted to the spindle? if rotor is turned w/o the hub & both sides are parallel, what difference would being mounted to hub make. i'm not doubting you, just trying to understand. also, should you do the same when you do rear disks? after you press the 3/4 ton hubs on the rear hub, should they be turned down to have them parallel w/14bff hubs?

The idea is that the hub won't be perfectly flat, unless it's been machined too -- and then the mounting surface of the rotor would need to be machined too.

When you mount the rotor to the hub, then, it'll be very slightly off, and so you turn the rotor as a unit, on the bearings and hub as it would on your truck. Otherwise, you're machining it to a less accurate standard... still better than .030" deep grooves but less than ideal.

As for drilling/slotting, note that drilling particularly will wear the hell out of the pads. The holes are supposed to be chamfered ("countersunk", whatever you call it) but even so, the trailing edges of the slots and holes tear into the pads something fierce. Plus, our rotors have the heat/dust vents down the center, so I'm not convinced that slotting them does all that much.

-- A

 

[4X4HIGH]

4x4high, i'm confused...the rotor needs to be put on your hub w/lugbolts pressed in place so the rotor is turned correctly? will the rotor lathe turn the rotors w/hub in place? does it mount the hub & rotor w/ the bearings, just like its bolted to the spindle? if rotor is turned w/o the hub & both sides are parallel, what difference would being mounted to hub make. i'm not doubting you, just trying to understand. also, should you do the same when you do rear disks? after you press the 3/4 ton hubs on the rear hub, should they be turned down to have them parallel w/14bff hubs?

Yes the rotors need to be mounted to the hubs with the wheel studs before they can be machined correctly. The hub/rotor assembly is placed on the brake lathe then the rotor is machined. The assembly is set up on the brake lathe centering on the bearing races so if new races are going to be installed they must also be installed before machining the rotor.

Yes when doing a rear disc conversion the rotors need to be mounted to the wheel hub with the studs pressed in place and then that assembly can be machined correctly.

 

[blazin_blazer]

good info, thanks 4x4high!

 

[Hogback Fabrication]

Yeah, the 3/4 ton calipers are physically the same size. Whether the larger piston is better or not degenerates into a nerd argument (same force spread over a larger area is less pressure per area, etc etc.)

Hydroboost IS great ... but it means a new master, booster and brake pedal. BTDT

-- A

The 3/4 ton caliper is physically the same size as 1/2 ton calipers; 3/4 ton calipers are directly interchangeable. The bore of the 3/4 ton caliper is just barely bigger (1/32"?), I can't believe that GM engineers decided such a stupid small difference was needed between 1/2 ton and 3/4 ton calipers. Honestly, I bet that the people who rebuild calipers for the chain stores don't even bother to differentiate between them (and why would they?). Seriously, there is no discernable braking difference between 1/2 ton and 3/4 ton stuff, only a couple percent.


As for machining a rotor while its attached to a hub, it makes sense in theory. The reason that it makes sense, and that is might be a recommended practice, is that the mechanic is lazy. You have to assume the hub is true, otherwise everything else is for naught. Then you have to assume that the mating surface between the hub and rotor is clean, flat, and free of debris (and this is where human error can come into play).


I'm sure I've replaced more than 50 sets of brakes, I've never had a set of rotors machined without the hubs that had any issues (though most are cars that have a seperate hub and rotor).

I've certainly worked on single vehicles that went 50-100K on each set of subsequent brake pads, no problems with any brake stuff before the pads wore out.


I'm an engineer, not a mechanic (though I seem to have played one through my high school and college years ) but I don't see too much benefit through machining the rotor with the hub attached. Unless, of course, there is some kind of foreign material between the two mounting surfaces. And then truing the rotor is not possible any way.

 

[blazin_blazer]

i was reading something here awhile back and instead of pressing the studs thru the hat and rotor, he used the lugs and nuts themselves, and an impact alternating back and forth tightning the lug nuts pulling the studs thru...is this an ok practice or should they be pressed in?

 

[lectric80]

i was reading something here awhile back and instead of pressing the studs thru the hat and rotor, he used the lugs and nuts themselves, and an impact alternating back and forth tightning the lug nuts pulling the studs thru...is this an ok practice or should they be pressed in?

It is a bad practice, and will ruin lug nuts as well as deforming the mating surface a bit. You should always have them pressed in properly.