My Rear Disc swap from drums observations

[John Cunningham]

Gotta say,, this is, and has been, an interesting thread. I applaud you guys who make the disc conversions to the 400 platform, with having to use a scan tool for the ABS to get proper bleeding, and then having to mess around with E-brakes, it's gotta be a lot of work.
I mentioned before, that for the use my rig gets, ('97 K2500 Sub, 8,600GVW,) that I didn't really "need" discs, and their is a lot of work and cost involved.
I'am actually thinking that, (for me,) an easy way to up-grade the brake system for little money/time, and effort, is to just pull-out the 14SF with its JD7 brakes, (13x2.5 shoes,) and replace the rear end with a 14FF that has the JB8 brakes, (13x3.5 shoes).
This will give 40% more braking effort in the rear, (that's a lot,) and the E-brakes and the other stuff should stay the same.
Ya know, It's almost unknown, but Chevy did have an RPO for a 1ton Sub, (9,200GVW,) I've seen one, it was a factory '96 with the 14FF, JB8,, and the front suspension, brakes, and transfer case from the 9,200GVW pick-up,, kinda rare, the one I saw was an ex Forest Service vehicle.

I had the big drums...3.5 brake pads and even bought the big wheel cyl...I did not put the new pads on and wheel cyl...I just did not like the pedal no matter if the drums were adjusted. I decided not to upgrade the drums because there is no way to stay on top of them..you really need to pull the drum to adjust them... did not like all the weight either and there is a huge different in comfort of the pedal. I hated driving the tuck before and now I enjoy it..........except for the lousy steering..the next fix

 

[John Cunningham]

JEEBUS!!! the stuff you are using in this thread to justify your thought process is off the damn wall. Does a drag strip have pitch on the road surface or is it dead flat? Do they have corners while braking down hill? How about some rain or sleet thrown in? A patch of oil? Pulling a tongue hitch trailer? Have a bunch of weight transfer to the front of the vehicle while hauling a load that has a high center of gravity like you're doing in a truck? And on top of all that you're not exactly making a panic stop at the end of a run on the drag strip are you? If you lock up your ass end while shutting down after a run you should probably never be operating a riding lawn mower let alone a vehicle. AND, AND....you used a parachute on your drag car keeping the rear from coming around no matter how hard you tried! LMAO! I've heard of comparing apples and oranges but I think you're comparing apples to pickles in this whole thread. I don't think it's any coincidence that most the people here that seem to know what they're talking about also say there is nothing really inherently wrong with the factory drums either. I was just going to swap in a late model rear end on mine but the more I read some of the posts here by the "experts" I think I'll just keep the stock setup on my '93 GMC K2500. All new brakes front and rear with quality components and I think it'll be as good as any of these crackpot setups. Oh, and did I mention that GM went back to drums or did you already know that?

Yea they did because they have so many warranty issues with the disc brake E brake......seizing up from non use cause all kinds of money to be spent on warranty claims. Its hard to get an ebrake to work with a disc and very easy with a drum and they figured that most people dont need disc brakes so will waffle back and forth with discs and drums over the years and only supply discs for people towing or who really want them. Otherwise the drums are without warranty claims and that is the only reason they are using drums ... for me taking out all the unsprung weight and clearly better braking and pedal feel was what it was about and I did achieve that........so whats the beef? By the way that came straight from a friend of mine who works in Warranty for GM. Its like fake news.......when you hear the facts it clears things up in a hurry?

 

[John Cunningham]

Not sure if this is any help, but when I had the stock rear drum brakes (adjusted correctly), I had to turn my willwood proportioning valve so that the rear brakes had the least amount of fluid, otherwise the rear wheels would lock up too soon. Now that I have the rear discs I had to set the proportioning valve so that the rear brakes have nearly the most amount of fluid to get the rear wheels to lock up.

So are you pleased you went to discs?

 

[454cid]

I did talk to a good friend of mine who is an engineer for GM.........and I will quote him " John many of the chevy trucks from the gmt 800,900 etc have gone back and forth with disc and drum brakes...

I think that's only the Non-HD trucks. I think once the HD's came out with discs they stayed with them, and only the lighter trucks went back to drum. I mention this, since your truck is a 1-ton.

I've never been one to use a parking brake with an auto either.... my cable stretched out or broke years ago on my truck. I had the rear brakes re-done and they were heating up. I was told it was the cable, so it got disconnected.

I know not to use the parking brake on a vehicle that hasn't seen regular parking brake use from my grandfather. For some reason he set the parking prake on his 83 Olds at the store, and the car wouldn't move after, because the parking brake jammed up. This would have been when the 83 Olds would still be considered a "late model".

I did have a situation where a parking brake would have been handy. I was parking on a short but steep hill, picking up a pizza. I got out, and noticed the truck sliding backwards. I think what was happening was the it was so slick out that the driver's side wheel was rolling backwards, and the passenger side was rolling forwards.

 

[sewlow]

[QUOTE="John Cunningham, post: 1033778, member: 22781"...so ask yourself and be honest...How many times have you used your ebrake the last 12 months......?? [/QUOTE]

Daily.
Multiple times daily.
In fact, it's the last thing I do before I get out of the truck. Every time.
Every damn time.
It's not even a conscious thought. Therefore, I don't have to ask myself whether I do or I don't.

Do you really think that I'd be such a hypocrite, standing here advocating the use of such & then not following through by refusing to lead by example?
You're slightly veiled back-handed insinuation that I'm a liar is not the first assumption that you've made in this thread concerning the knowledge of others that have offered their experienced input. In fact, it's rife throughout this thread.
If insults & chest-pounding is you're way...well...let's put it like this...I've seen many of you're type come & GO through this forum over the years. It's only a matter of time.
So, before I exit this ***********, let me just say as an engineer (Yes. I am.) to a non-engineer...you're not. ...and it shows. You don't even know how to bleed the brakes on these trucks properly. Jeez!
Public roads & highways are not the place to be experimenting with backwoods redneck 'It came to me in a dream' cobbled-together-on-cinder-blocks-in-the-trailer-park, just-making-it-up-as-I-go-along brake system redesigning practices.
I take comfort in the fact that you're truck & mine will never inhabit the same road at the same time.
I pity & fear for those that do.
G'day.

 

[1BigCarrot]

Mate, that is one nice ride.

 

[John Cunningham]

[QUOTE="John Cunningham, post: 1033778, member: 22781"...so ask yourself and be honest...How many times have you used your ebrake the last 12 months......??

Daily.
Multiple times daily.
In fact, it's the last thing I do before I get out of the truck. Every time.
Every damn time.
It's not even a conscious thought. Therefore, I don't have to ask myself whether I do or I don't.

Do you really think that I'd be such a hypocrite, standing here advocating the use of such & then not following through by refusing to lead by example?
You're slightly veiled back-handed insinuation that I'm a liar is not the first assumption that you've made in this thread concerning the knowledge of others that have offered their experienced input. In fact, it's rife throughout this thread.
If insults & chest-pounding is you're way...well...let's put it like this...I've seen many of you're type come & GO through this forum over the years. It's only a matter of time.
So, before I exit this ***********, let me just say as an engineer (Yes. I am.) to a non-engineer...you're not. ...and it shows. You don't even know how to bleed the brakes on these trucks properly. Jeez!
Public roads & highways are not the place to be experimenting with backwoods redneck 'It came to me in a dream' cobbled-together-on-cinder-blocks-in-the-trailer-park, just-making-it-up-as-I-go-along brake system redesigning practices.
I take comfort in the fact that you're truck & mine will never inhabit the same road at the same time.
I pity & fear for those that do.
G'day.[/QUOTE]

This is the most interesting posts to date on this thread. I have never heard of setting an ebrake multiple times daily. Every time I get out of my cars and trucks I select park and turn the key off. I have never set my ebrake not even once this year on the 2 cars and 2 trucks I own....and I cannot think of a reason why I would. You should poll this forum about who sets their ebrakes several times a day. I can only tell you that your probably the only person I know so personal with his ebrake. Your almost violent language towards me indicates other things about your demeanor. Have a great life and keep stepping on the Ebrake pedal multiple times a day.

 

[454cid]

This is the most interesting posts to date on this thread. I have never heard of setting an ebrake multiple times daily. Every time I get out of my cars and trucks I select park and turn the key off. I have never set my ebrake not even once this year on the 2 cars and 2 trucks I own....and I cannot think of a reason why I would. You should poll this forum about who sets their ebrakes several times a day. I can only tell you that your probably the only person I know so personal with his ebrake. Your almost violent language towards me indicates other things about your demeanor. Have a great life and keep stepping on the Ebrake pedal multiple times a day.

Most people don't use them if it's an auto. If it's a manual, some people will simply leave them in gear, but it's better to use the parking break. If he uses the parking break, then it's going to be multiple times per day. I don't know why you would think that to be so unusual. It would be just like locking your doors a the store..... you're not going to lock them at Home Depot, and then leave them unlocked at Walmart, you're going to lock them every time.

If I were parking where it was always snowy, or hilly, I'd probably be using my parking brake. If you live were it's warm and/or flat, it's not going to seem at necessary.

 

[letitsnow]

So are you pleased you went to discs?

Yes, very much so. To be fair though - my stock drums were all worn out. I had to spend some money either way, and chose the disc conversion because I prefer disc brakes. Ever since my old dirt bikes had drum brakes (many moons ago), I realized that I hate drum brakes.

My brakes work really well now. Most stock gmt 400's that I have owned or driven were scary if you had to stop quickly. You never really knew which way they were going to pull, or if the rears would lock up too soon and be rendered useless by the abs. Now I can drive in any major metro area in stop and go traffic without feeling like I might die.

For somebody who just putts around on country roads, it probably wouldn't matter.

 

[Crookedaxle]

Yea they did because they have so many warranty issues with the disc brake E brake......seizing up from non use cause all kinds of money to be spent on warranty claims. Its hard to get an ebrake to work with a disc and very easy with a drum and they figured that most people dont need disc brakes so will waffle back and forth with discs and drums over the years and only supply discs for people towing or who really want them. Otherwise the drums are without warranty claims and that is the only reason they are using drums ... for me taking out all the unsprung weight and clearly better braking and pedal feel was what it was about and I did achieve that........so whats the beef? By the way that came straight from a friend of mine who works in Warranty for GM. Its like fake news.......when you hear the facts it clears things up in a hurry?

So now you're backtracking a bit aren't you? My point is that you're bending over backwards trying to convince yourself (more than us) that you've improved your brakes tenfold by using the most asinine convoluted unrelated analogies I have seen in a while. NOW you're telling us what most here already knew and in fact some have told you multiple times. Disk brakes and drum brakes put together with quality components and properly used/maintained are a horse a piece with advantages and disadvantages to each ESPECIALLY on a pickup truck and that GM went back to drums strictly for warranty claims. DUH!