Rear brake upgrade: 11” to 13”
 

Yeah I know, most people are busy jumping through their own pie hole junking rear drum brakes on their 4x4's for rear disk brakes but I don’t totally buy into the rear disk swaps especially with using El Dorado calipers. I hated working on El Dorado calipers when they were on El Dorados let alone to bolt those turds on my toy. No way! The late model GMT800 rear disk swaps are worthwhile but the parts are too pricy.

Anyway, as many of you know, I scrapped my dad’s K20 wrecker last week and plan to swap the wreckers axles into my Suburban but the wrecker had 13” rear brakes. My heavy K10 could benefit more from the larger 13” brakes than the Suburban so I renewed everything on the 13” brake system and swapped them over to the K10 today. WOW! With the combination of the hydroboost I swapped on a couple years ago along with these 13” brakes the big heavy truck stop on a dime now! The dang park brake finally works now too. Actually, it feels like it stops better than my stock Silverado HD with rear disks.

On with the pictures…

Off with the little 11”s
http://farm9.staticflickr.com/8008/7...bee72e5b_c.jpg

http://farm9.staticflickr.com/8161/7...cf38dfa3_c.jpg

Check out the difference when the 11’s are laid next to the 13’s. I installed the new shoes, hardware and e-brake cable on the 13” backing plates last night so it make the job quick and easy today. That 13” drum is a heavy mofo!
http://farm9.staticflickr.com/8152/7...cc338dd3_c.jpg

http://farm9.staticflickr.com/8024/7...0a02c60e_c.jpg

http://farm9.staticflickr.com/8014/7...a3450442_c.jpg

http://farm9.staticflickr.com/8153/7...8033cc39_c.jpg

The big 13” drums stick out much further behind the wheel
http://farm8.staticflickr.com/7137/7...39a9cd40_c.jpg

Rear view of the 11’s before tear down
http://farm9.staticflickr.com/8285/7...289c880d_c.jpg

The only downside is the truck gained more weight but on the other hand, Sunday I replaced the rear winch cable with Viking winch rope so it somewhat balances out with losing some weight and gaining other weight. The junk Smittybilt winch broke yet again so while it was apart I figured it was time to ditch the wire cable...that is where the Viking winch rope came on the scene. I’ve used the Smittybilt winch about 3 times and it has broken 2 of those times. This past time the motor wouldn’t stop running once I hit the switch. This time it needed a new relay pack. Errr :lol:

Now I have to get to work on rebuilding these 11" brakes and finish getting the D44 front axle ready for the Suburban.
http://farm8.staticflickr.com/7136/7...696e2d83_c.jpg

Re: Rear brake upgrade: 11” to 13”
 

Can you run us through the process of tightening down the spindle nuts etc when putting the drum/hub back on?

Re: Rear brake upgrade: 11” to 13”
 

Just tighten the inboard spindle nut until your elbow clicks then install the lock washer and outer spindle nut. Tighten the outer spindle until the veins in your forehead stick out. :lol:

Hehe, just like asking my mother in-law for a recipe. She doesn’t measure anything just a dash of this and sprinkle of that. In all reality just tighten the inboard spindle nut enough to set the bearing preload then back it off a tad. The outer nut just needs to be good and snug. I’ve been messing with full floaters since I was in high school so I never really torque anything on these after the first few, just go by feel.

One recommendation is to replace the spindle nut assembly when you have these full-floaters apart as the locking ring/washer dealeo tends to get pretty beat up after being taken a part even once. The Dorman Part number for the spindle nut kit is 05310, Napa’s part number is BK 6301660

Here is a wasted lock ring dealeo. Don’t reuse one that looks like this as I have seen rear hub/wheel assemblies separate from the vehicle when they fail and the spindle nuts back off.
http://farm5.staticflickr.com/4133/5...7b2a563e_z.jpg

Here is the new Dorman spindle nut kit. Best $45 per side you can spend when bolting a full-floater back together.
http://www.dormanproducts.com/images.../05310-005.JPG

Re: Rear brake upgrade: 11” to 13”
 

I did this swap several years ago on a 3/4 ton 14 bolt that I used in my dually...those 13" drums are massive!

On my cab & chassis rear I'm working on now it uses a different type of spindle nut that gets keyed to the spindle and has a wire type retainer..pretty slick way of locking the spindle nut.

Re: Rear brake upgrade: 11” to 13”
 

I would like to do this on the 14 bolt I have in my 75 k/20. are all the 13" brakes the same on these, is there anything I should stay awAy from? 3/4 and 1 ton the same? im sure ill have to by a couple of those kits as mine have been apart several times before
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Re: Rear brake upgrade: 11” to 13”
 

No, actually….not all are the same. The only difference I found is the 1984 and later rigs, albeit 11” or 13”, have a different e-brake connection at the brake drum backing plate. The earlier ones have a two bolt fastening method at the brake drum backing plate while the later have are a push in design. The good news is the Bendix backing plates are very universal in that a backing plate from a 9.5” semi-float POS axle with 13 x 2 brakes is the same as the backing plate for 13 x 3.5 on the big 10.5” full-floaters.

In my next situation where I will be putting a ’78 10.5” axle in an ’89 Suburban I must use the ’89 Suburban’s 9.5” axles backing plates on the 10.5” axle in order to use the later design park brake cables. YES…….Confusing, I know! Since I run manual transmission is almost everything I own a park brake is a must!

Got to love GM for their consistency in parts interchangeability though! Just figuring out the correct concoction of parts to make it all work is fun part. :lol:

Re: Rear brake upgrade: 11” to 13”
 

Once again, Larry, you've educated me! I've been planning on doing a disc brake conversion on the 14 bolt I bought for my 1 ton build. But, I never realized it had 13" drums. Now, I may not switch them out....

I was planning on using a driveline e-brake/Cutting Brake set up for the np205...to keep or not. It still could be useful to have and I already paid for it!

Re: Rear brake upgrade: 11” to 13”
 

I remember when I converted my 14 bolt full floater with 13" drums to disk brakes, and weighed the pile of parts I took off when done. My truck lost 75 lbs that day.

I converted the HO72 Eaton to disks too. Old Creek, I'd be interested in learning more about that "Cutting Brake" / Parking Brake for the NP205? What can you tell us about it? Any pics of the setup?

Thanks.

Re: Rear brake upgrade: 11” to 13”
 

Check High Angle Drive Line in Cal: http://www.highangledriveline.com/e_brake.html

I've never used one. It appears that it would have greater holding power than regular drum e-brakes but I'm guessing at that...

Re: Rear brake upgrade: 11” to 13”
 

Larry,

Very good information you posted.

Interested in upgrade to 13" drums too, for Dana 60, is it correct that your discussion above is for Eaton rear axle? How much applies to '71 Dana 60s with 12x2.5 brake shoes?

A few questions, on possibility of upgrading a '71 Dana 60 12x2.5 brake to 13 inch drums. Thinking of two/three possibilities while keeping stock axles:
1). We're their Dana 60 applications that used 13" drums which can be switched to '71; and

2). Can Dana 70 13" brakes be switch, all from backing plate out. Maybe 80s Suburbans?

3). Other option, e.g. 70s Fords 3/4 ton that used 12x3 brake shoes, chevy dually brakes



Thanks,
Les

Re: Rear brake upgrade: 11” to 13”
 

My rear axle is a Corp 10.5 14 bolt. Much different than Dana rear axle. Not sure what all can be swapped in the Dana rear axle world as I've never messed with them other than just maintenence work.

Re: Rear brake upgrade: 11” to 13”
 

I'm interested in the same idea, upgrading dana 60 drums with bigger drums. I'll be watching this post. looking forward to good info.

maybe dana 60 drum brake upgrade should be a whole new thread????

Re: Rear brake upgrade: 11” to 13”
 

I am doing the same thing Larry, swapping a CUCV rear under my K5. Going to keep the 13" drums.

Re: Rear brake upgrade: 11” to 13”
 

Larry, thanks for more information on which axles you upgraded to 13".

Mike, agree going to start new thread for Dana 60 brake upgrade.

Les

Re: Rear brake upgrade: 11” to 13”
 

Any idea who makes an e-brake kit for the drive line on a Dana 60 2x4?

Re: Rear brake upgrade: 11” to 13”
 

Are you saying you have a drum brake on the driveshaft of your C/20? I have seen those on the C/30s with 11K# axle option. If you show a picture we might know exactly what you have

Re: Rear brake upgrade: 11” to 13”
 

No. I'm saying I have a Dana 60 rear and would like info on a disc e-brake mounted to the piniun.

Re: Rear brake upgrade: 11” to 13”
 

Awsome post... I'm getting ready to do a differential swap on my 1984 GMC Camper special that has a 9.5" semi floater and the 13" drums which has been making noise for years, but now the pinion seal failed and the noise has gotten much worse.
I acquired a 1977 C-20 with the heavy commercial suspension (G51?) with a 10.5" 14 bolt and the same 13" brakes. I'm keeping that huge front sway bar !!!.
I noticed, the E brake set up is completely different between the two trucks and was flummaxed as to what to do, but .... if... the backing plates between the two differentials will interchange, then I'm back in business. I just wish the drums and brake parts would interchange also.
Anyway.. great post.

Re: Rear brake upgrade: 11” to 13”
 

Sorry for the newb question.

I can't seem to find a definitive answer...

Will a square body (80's) 2WD 3/4 Ton 14 bolt FF axle fit a '84 K10 shortbed?

I can't figure out what the differences are after a VERY short search tonight. Was thinking that I had seen a link on the pirate site to an axle buyers guide.

I can get my hands on a couple of different 80's 2WD 14 Bolt FF axles, but want to make sure. I'd rather not have to weld perches/shock mounts.

EDIT: I found this site, (http://www.pirate4x4.com/tech/billav...ble/index.html) which makes it sound like the axle would work... but, I'm hoping someone will chime in and clarify.

Thanks

Rob

Re: Rear brake upgrade: 11” to 13”
 

The short answer is yes, a 2wd or even 4wd ¾ ton rear axle will bolt right into a ½ as the perches are in the same location. 1 tons have different spring perch locations where the perches need to be cut off and moved when installing a 1 ton rear axle into a ¾ ton or ½ ton.

As an example, the 10.5” FF that has been in the back of my 1978 K10 for the past 20 years came from a 1976 C20. That said, keep in mind 10.5” 14 bolts get harder to find in ¾ (20 series trucks) after 1980 as most ¾ tons were equipped with the 9.5” 14 bolt semi floater beginning in 1981 as part of the weight reduction thing GM had going on. 10.5” full floaters were still used albeit typically only in ¾ tons with big blocks or diesels. A 2wd Suburban all the way to 1991 with a 454 or diesel will have a 10.5 full floater 99% of the time. The spring perches line up with a ½ ton too so Suburban make great vehicles to pirate axles from.

Edit: one last thing... don't forget the obvious pieces that need to be dealt with when doing a full floater swap. The U-bolts, spring plates (u-bolt plates need to come from the axle donor truck), u-joint and park brake cables need to be dealt with as well.

Re: Rear brake upgrade: 11” to 13”
 

and 2wd shock tabs were flip flopped on the axle .

Re: Rear brake upgrade: 11” to 13”
 

Some, but not all. I've seen a few different shock tabs in 3/4 ton 10.5" full floaters. My buddy just recently got one out of a 77 C20 with really tiny shock tabs where as others I have seen had longer tabs for longer shocks.

Re: Rear brake upgrade: 11” to 13”
 

Good Stuff!!! Flopped as in the direction, front to back is different?

Now... I just need to find some 13 inch mounting brackets. No plans for disk brakes for me.

Thank you!

Rob

Re: Rear brake upgrade: 11” to 13”
 

As always an awesome stock looking upgrade Larry.

I got rid of the rear D60 for an '05 14B disc axle from a 2500 HD. Got a good deal but TBH, really can't see a difference in stopping power between the 60 and 14B. One HUGE difference as you had noted was that the parking brake on the disc axle sucks compared to the drum axle. It holds and has never slipped but also has never inspired the confidence that the drum brake did. I personally think that the surface area of the disc parking brake shoe isn't nearly 1/3 of the size of the drum.... and with 13" drums, its probably 1/4 of the size (probably less) than the drums.

Re: Rear brake upgrade: 11” to 13”
 

I’ve seen a few different shock brackets orientations on ¾ tons but often 1 tons the shocks can be on one side of the axle instead or staggered. You should be fine with the axle you are using.

Thanks! Yeah, I have a 2001 Silverado HD with a manual trans so I use the park brake constantly. While the pedal is easy to push and it has never rolled away it does not have a confident feeling to the park brake. It is also easy to drive off with the park brake fully applied whereas the big drum brake rigs give the feeling they are drilled into the ground.

Actually, this thread is 5 years old but it is ironic it got pushed to the top as the truck is under the knife again for an axle upgrade. Ditched the Detroit locked 14 bolt and went with a wider G-van 14 bolt with an ARB air locker. Story HERE. Renewed all the drum brake pieces while I was at it....the truck has turned a lot of highway and off-road miles in 5 years

Re: Rear brake upgrade: 11” to 13”
 

LMAO. Ass transplant! I gotta register there. Nice 14B. I gotta ask, where in the hell does the Oreo come into play? Does it help calibrate the dial indicator :haha:

I didn't read it all of the way through. Do you like the ARB? Ive got a Gov Loc. It hasn't given me any problems but if it were to go, I was looking at either ARB or an OX Locker type setup. I have a "thing" about things locking up when Im not expecting it.

Re: Rear brake upgrade: 11” to 13”
 

:lol: like I mentioned in that thread….my pal Bill needs to be motivated with food. Got to keep treats in front of him like a dog to keep him focused :lol:

The verdict is still out on the ARB as the project is far from complete. I just got the axle under it yesterday afternoon and still need to set up the pinion angle and shock arrangement. I haven’t even gotten a compressor or air tank or even started laying out the front Bilstein 7100 shock layout yet. Got a long ways to go but I have until June when Desert Trip 2017 is booked.

https://c1.staticflickr.com/3/2837/3...cc3e8c8d_c.jpg

The G-Van axle looks wider...My eye micrometer says about 1.5” on each side :smoke:
https://c1.staticflickr.com/1/645/33...f24a1b15_c.jpg[/url]

Re: Rear brake upgrade: 11” to 13”
 

Funny how you say that its wider. Does it even out with the front?

I had no clue that my old 60 was nearly 3 inches narrower than the front until I got the 14B home and found it was actually 5 inches wider than the 60. After the initial freak out subsided, I realized that it actually lined up the front / rear track a little better. 3/4" wider in the rear on each side.

I keep thinking that maybe if I keep some Oreos around, that the kids may help out a little more.... realistically though, Id end up needing an assplant :lol:

Cant wait to hear how the ARB works for you. If anyone would use it like its supposed to be used, it would be you.

Keep up the good work! Looks great!

Re: Rear brake upgrade: 11” to 13”
 

true van width rear 14ff is 70" wms to wms . reg srw pickup rears are 67" and c&c is 64" . a dana 60 srw front is 69" .

Re: Rear brake upgrade: 11” to 13”
 

I'm going the other way, from 13 to 11 inch drums. I'd rather lose the weight than carry around a capability I'll never use. I'm swapping in a 14FF/dana 60 combo from a cucv into my 85 3/4 ton.

My only question is regarding the wheel cylinders. Are they different diameter/capacity and if so, does it affect the stock master cylinder?

Thanks for sharing the info Larry.

Mike

Re: Rear brake upgrade: 11” to 13”
 

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Re: Rear brake upgrade: 11” to 13”
 

I went with discs on my 14bff so FREE to a good home 13"drums and backing plates. Of course you have to pick them up.

Re: Rear brake upgrade: 11” to 13”
 

Can anyone help???
I have a 1987 Chevy suburban 2500. It is a 350 gib with th400 trans. 4X4 it started life with a 9.5” semi floating rear. The carrier had a lot of slop and I had a 10.5” full floating rear out of another truck. Ever since I installed it the stopping power has been horrible. All of the rear brakes are new except drums which were cut and well within tolerance. I didn’t change the booster or master or proportioning valve. Also my truck still has the rear weight/level sensor and the brake lines do go through it. But they always did. My other two suburbans are a 1982 3/4 two 2wd. And I can lock it’s brakes up if I push the pedal too quickly. It is a 9.5”. Am I just expecting too much from the 10.5” brakes? Thank you in advance for any help or suggestions I really appreciate it. This is my plow truck and I’m trying to get it figured out before the snow flies. Again thank you!

Re: Rear brake upgrade: 11” to 13”
 

first thing those load valves love to go bad and freeze up . by pass it .

then looking up the 87 burb master cylinder part #'s .

11" rear brakes was aluminum / plastic tank master with small bore size .

13" rear brakes was cast iron master with bigger bore for more fluid flow .

so if bypassing and bleading the rear dosnt help the next step is bigger master to match the bigger rear brakes .

but also double check the brakes are adjusted in the rear . self adjusters dont do crap most of the time . jack up the rear so tires are off the ground and click them up till just starting to scuff the drum face .

Re: Rear brake upgrade: 11” to 13”
 

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Re: Rear brake upgrade: 11” to 13”
 

Post revive... Activate!! Ok I've got a full float DRW Dana 70 I a 71 GMC I'm currently rebuilding the 13" rear drums on from the ground up and I'd appreciate any help given. It appears to have GM hardware (alot seems to be missing, and to be honest the rear brakes never worked since I got it) Here is what I've got so far: 1)they never worked, except for the parking brake, 2) The wheel cylinders were corroded to high heaven and siezed solid... The part in the axle had an International Harvester part number on it and has a 1.25 Bore size, 3)shoes were cracked and about 2mms away from the rivits, I have no idea what the correct brake shoes are supposed to be. Every parts store including GM says it "should be either the 451s or 320s... But I personally I can't tell a difference in person and the PO loused up whatever shoes they bought to accommodate the parking brake by drilling an extra hole. 4) there was no self adjuster hardware on the passenger side... At all... None. The pictures I was able to find on here and the internet lead me to buy the adjuster kits (both sides). Now as I'm putting the Passenger side back together... Things aren't lining up IF I use the parking brake spreader bar...should I groove out one of the notches(it is only about a 1/4 inch off And I've given the parking brake as much slack in the line as I can)? Or should I buy a new spreader bar? This one seems really wide/long... Not sure of the correct terminology. I'm sure I'm forgetting something but Any help would be greatly appreciated.