Light duty to F44

[SNCTMPL]

Hey guys I’m getting started on a project with my son and was trying to figure something out that I have not been able to find the answer to. He’s got an 89 rclb with the light duty suspension in it, and we are going to buy all new components for the steering, suspension and brakes. I want to get the bigger brakes for it.

If I get steering knuckles from an f44 truck, and then buy the parts for an f44, is that all that is needed, or am I missing something else?

 

[Schurkey]

I want to get the bigger brakes for it.

Look at the SPID decal in the glovebox. A regular-cab truck likely has JN3 brakes--the weakest power brakes ever put on a GMT400. That's what my '88 K1500 had. They were so pathetic that GM quit using them in the early-'90s.

The difference between JN3 and JN5 is:
Rotors (thicker, but same diameter. The thicker rotors need the matching hub/bearing assemblies. I just used the entire steering knuckles from the donor vehicle.)

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Calipers (larger piston, but "low drag" design like the JN3. The pads are essentially the same except the JN5 has a bigger spring-clip on the inboard pad to fit inside the larger piston. I think I just stretched the spring clip on my pads since they were still usable.)

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Master Cylinder (1 1/8" main bore, 40mm Quick Take-Up bore. JN3 is 1", and 32 or 36mm QTU, I forget which.)

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Brake booster (larger)
(Photo coming...someday.)

The RWAL and rear brakes are the same. The rear brakes SUCK.

If there are differences in the combination valve, I don't know about 'em.

The front brakes, master and booster can come off of an extended-cab K1500 or a light-duty K2500. A newer regular-cab truck should also have JN/JB5 brakes.

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My '88 had no front sway-bar. I stole one off the same extended-cab donor vehicle that supplied the front brakes. Very worthwhile. 2WD is different from 4WD. Be sure to get the correct one.

 

[Schurkey]

The JN6 is the same as JN5 except the rear brakes are the much bigger, much better Duo-Servo 11.x drums instead of the crappy 254mm (10") leading-trailing shoe drums.

Ideally you'd swap rear axles with a 6-lug K2500 to get the bigger, stronger 9.5" ring gear axle which will also have the better 11.x rear drums. The rear axle on a C2500 is different width than a K2500. Axles from Tahoe/Suburban may have mounts for a rear sway bar.

Axle rotated 90 degrees, wheel cylinder is at top of assembly.

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Nobody uses the park brakes, so the park brake cables are usually seized and perhaps cut off. Aftermarket replacements are inexpensive, but lower-quality than OEM. The (now discontinued) Thexton #450 tool for releasing the spring-clips on the park brake cables makes the job substantially easier.

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[BuiltToWork]

Nobody uses the park brakes, so the park brake cables are usually seized and perhaps cut off. Aftermarket replacements are inexpensive, but lower-quality than OEM. The (now discontinued) Thexton #450 tool for releasing the spring-clips on the park brake cables makes the job substantially easier.

Nice write up [B][COLOR=rgb(239, 239, 239)]Schurkey[/COLOR][/B] . Is tool #450 used for the springs on the drums AND the parking brake or just the parking brake? About to tackle my drum job and have always used screwdrivers and swearing.

 

[xXxPARAGONxXx]

For releasing the parking brake cable from the backing plate, Lisle 40750 works well.

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For compressing the spring at the end of the cable to install it onto the brake shoe, I bought a tool on Amazon sold in the UK (if I recall), Laser 3739. (Vise Grips would work well though, but may marr the metal.)

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[BuiltToWork]

For compressing the spring at the end of the cable to install it onto the brake shoe, I bought a tool on Amazon sold in the UK (if I recall), Laser 3739. (Vise Grips would work well though, but may marr the metal.)

Thank you for the info!

 

[Schurkey]

Is tool #450 used for the springs on the drums AND the parking brake or just the parking brake?

Only the three spring-tabs on the anchor for the park brake cable, where it pushes through the backing plate.

For releasing the parking brake cable from the backing plate, Lisle 40750 works well.

MAYBE better than the Thexton tool. I've never used the Lisle, but it looks like it'd be just fine.

For compressing the spring at the end of the cable to install it onto the brake shoe, I bought a tool on Amazon sold in the UK (if I recall), Laser 3739. (Vise Grips would work well though, but may marr the metal.)

I've just pulled on the cable while pushing on the spring. It's kind of a three-hand bit of work. Thanks for the kick in the asp. I don't see the Laser tool on Amazon, but the Lisle 44210 seems similar, and is now ordered.

www.amazon.com/Lisle-44210-Universal-Emergency-Brake/dp/B00HFSQ6BM/ref=sr_1_5?crid=U52DAT6E26IS

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Laser must be a common English tool company. Last summer I bought the Laser-brand special valve-depressor for changing valve clearance shims on a Yamaha FJ1200. Shipped from England.

The other "essential" brake tools are:

A brake hold-down spring compressor. Mine is a Mac, older than most of the folks on this forum. It's the larger size. If I were replacing it, I'd get one that does large and small springs.

www.amazon.com/GEARWRENCH-Universal-Brake-Retaining-Spring/dp/B0002SQU7W/ref=sr_1_4

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A star-wheel adjusting spoon. I've got several, with various bends. But any one of them is better than none of them.

www.amazon.com/Lisle-50700-Brake-Adjusting-Tool/dp/B0002SQU6S/ref=sr_1_2?crid=3CS9GVE0DF5HV

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And some sort of brake shoe return spring remover/installer.

I have the "pliers" style--an ancient Craftsman from the middle-1970s, somewhat like this one:

www.amazon.com/Performance-Tool-W175-Spring-Pliers/dp/B00BR1BV8Q/ref=sr_1_1?content-id=amzn1.sym.ded350ec-4301-4b42-a09b-d79e6f40c7e0%3Aamzn1.sym.ded350ec-4301-4b42-a09b-d79e6f40c7e0

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But there are other styles. The two plier "handles" remove and install the return springs. I've never seen anyone use the clamping part of that style tool. I don't know what it's for.

Some guys are wild for brake-bleeder wrenches; and again there's many styles and sizes, with the wrench part bent in different directions. When it's me, my first choice is a six-point socket and the longest 3/8 ratchet handle I own--not for leverage, but for control. Support the ratchet head with your other hand so there's no side-force on the bleeder screw.

Working on the hateful 254mm leading/trailing shoe brakes requires different tools, mainly a needle-nose vice grip and/or a large scrapmetal bin.

 

[BuiltToWork]

Thanks again Shurkey, I went with this because it has a case:
KIT

 

[Schurkey]

I've never seen anyone use the clamping part of that style tool. I don't know what it's for.

Thanks again Shurkey, I went with this because it has a case:
KIT

Thank YOU. There's a photo on that page of how to use the clamping part of the "Brake Spring Pliers". Forty+ years, I couldn't figure this out on my own. If I wasn't so good at doing it with a different tool, I'd have to try this some day.

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[SNCTMPL]

Look at the SPID decal in the glovebox. A regular-cab truck likely has JN3 brakes--the weakest power brakes ever put on a GMT400. That's what my '88 K1500 had. They were so pathetic that GM quit using them in the early-'90s.

The difference between JN3 and JN5 is:
Rotors (thicker, but same diameter. The thicker rotors need the matching hub/bearing assemblies. I just used the entire steering knuckles from the donor vehicle.)

You must be registered for see images attach

Calipers (larger piston, but "low drag" design like the JN3. The pads are essentially the same except the JN5 has a bigger spring-clip on the inboard pad to fit inside the larger piston. I think I just stretched the spring clip on my pads since they were still usable.)

You must be registered for see images attach

Master Cylinder (1 1/8" main bore, 40mm Quick Take-Up bore. JN3 is 1", and 32 or 36mm QTU, I forget which.)

You must be registered for see images attach

Brake booster (larger)
(Photo coming...someday.)

The RWAL and rear brakes are the same. The rear brakes SUCK.

If there are differences in the combination valve, I don't know about 'em.

The front brakes, master and booster can come off of an extended-cab K1500 or a light-duty K2500. A newer regular-cab truck should also have JN/JB5 brakes.

You must be registered for see images attach

My '88 had no front sway-bar. I stole one off the same extended-cab donor vehicle that supplied the front brakes. Very worthwhile. 2WD is different from 4WD. Be sure to get the correct one.

Thank you for the very detailed reply. That gives me a lot to go off of. The rpo codes are a little lacking on this thing, the only brake code it has is J50 BRAKE SYSTEM,VACUUM POWER
J50 BRAKE SYSTEM,VACUUM OR HYDRAULIC POWER(WITHOUT DUAL REAR WHEELS)
Now I just have to go find a donor.
Thanks again.