New Here and... First Question on 71 K20 Brakes

[A.Bursell]

Hello,

Been looking for the right truck for a long time, and I think I've finally found it. Will be picking it up at the end of the week. It's a 71 K20.

This is my first classic vehicle. I have owned many that were 10-15 years old at the time, but never anything as early as this. As such, I will be asking lots of questions. I've been lurking here and soaking up info, but only so much I can get without having my own to look at and ask questions about.

When I first drove the truck, I suspected it had a bad booster, as it really felt like manual brakes. Before I could make an offer, the owner had a mechanic look at it and scheduled a replacement of the booster. That is why I have to wait until the end of the week to pick it up. I also noticed some fluid around one of the rear wheels, not sure if from the rear axle or wheel cylinder. Couldn't tell.

One of the first things I would like to do on this truck is replace the brakes, so I feel good about driving it. How far should I go? I have no issue with replacing the master cylinder (if not done with the booster replacement). Should I? Should I also consider replacing the hard lines? Are they known to cause issues? I would also like to replace the rubber lines, as well as calipers, etc. just because of age. Am I ok buying these parts from RockAuto.com or should I source them elsewhere? I also plan to pick up the service manuals to help me along my journey.

Will I find any surprises with the brakes on this truck or is it pretty straightforward? Anything else I should inspect or consider replacing while things are apart?

Lots of questions I know! Thanks,

Adam

[s_nova69]

Welcome. I have never been the first to respond so I am jumping on this

I have had and do have several of these trucks and have a good experience base from which to lend advice.

Brakes are what save you from smashing things only second to the tires.
That being said a complete overhaul of the brakes would be very beneficial. By complete I mean new rubber lines, MC, pads, shoes, rotors, drums if needed, calipers, hardware, and wheel cylinders are all pretty easy parts to get from almost anywhere. Lots of people use them but I never have as I have local parts houses I have worked for in the past that I buy from.

Completing the entire system with new parts also helps narrow down problems if they occur. I would not replace a hard line unless it was smashed or broken.
If you do do the entire system do one side at a time to be able to reference the other and don't throw anything away until you are done. Lots of people would say not to throw it away then either.

I would recommend getting some ebc green stuff or hawk pads for the front. Hawk was being clearances from pep boys a while ago and there might still be some out there. Most caliper suppliers do a good job of rebuilds or new calipers as they are the same on almost every gm build truck for 20+ years. You could always upgrade to the new dual piston ones from wilwood. They aren't that expensive.

Make sure to measure the shoes that you have before ordering because there is no way to tell what they are unless you measure them. New wheel seals and axle seals are cheap and you will already have it torn down so put those in too. I haven't rebuilt the hubs etc on this gen truck before but it might be worth it depending on what your plans are with this truck.

Long winded but hope it helps. Ask tons of questions there is always people to lend their knowledge here on any subject
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[vectorit]

Welcome to the forum!

When it comes to brakes, one should go all out in my opinion.
The rear are drums, and getting them completely overhauled is cheap.
The fronts, make sure the discs are not worn beyond factory recommended specifications. This is probably where you will spend more money, since being a 4wd it takes more time to take apart and reassemble.

Always a good idea to replace the rubber brake lines, especially if they are the original 40 year old ones.

If there is fluid on the inside of the tires spinning out, that is brake fluid or a bad axle seal depending on the model axle you are running. If it's brake fluid then fix it while the booster and master are getting replaced, otherwise all that work will be for not.

Is the truck lifted? If so, stock brake lines may be too short. Make sure, before spending money on stock length brake lines. Since the stock ones will be too short, and will eventually sooner than later fail due to over extending.

Rock Auto is great for sourcing parts, and their prices are very competitive. Though many times your local NAPA store will have the part you are looking for when it comes to brakes on your year rig, so check there first to save time and money spent on shipping.

Again, welcome to the forum!

Post plenty of photo's of your new rig, we love pictures here so don't hold us in suspense to long ok

[A.Bursell]

Thanks guys. I have done brakes before, but never on one of these trucks. I'm hoping that it won't be too different from my prior experience, we will see! I like the idea of replacing everything, that was my original idea and I am on board with it.

As for the truck being lifted, it does seem to have some type of a lift setup on it. That is one of the questions I was going to post about. I will take pics when I can and post them looking for info. It is all spring, I do not recall seeing blocks. I rubbed the dirt off one shock and saw it was Rancho. Two shocks up front. Maybe this will help identify the kit and help me decide if I want to keep it or not.

Thanks again,

Adam
Posted via Mobile Device

[ole dollor]

welcome to the board....i also agree that brakes are the most important part of any vehicle....even if your pushing it ...it still needs to stop when you get there...have fun with your new ride....make it yours.

[Indyuke]

Welcome from to the boards. I myself am from Marysville as well. Maybe I'll see you cruising around one of these days.

[Vintage Windmills]

As mentioned, the job might snowball on the front end since the brakes are behind the hub. Not your usual "remove the wheel, pull two bolts" setup you are used to.

Nice writeup, saa. I might be contacting you once i reach this point on my K20. Especially for the places in california you mentioned.

[A.Bursell]

I did brakes on a Ford truck I had where I had to disassemble the hub to get to the rotor. It required a special socket to take it apart and put it back together. Is that similar to what I will be getting into here?

I plan to get the service manual, but can you clue me in to exactly what I am looking at? Are the rears standard drums like I am used to or will it be different due to the heavy axle setup?

Adam

[A.Bursell]

Oh, and thanks again for the welcomes. I'd like to meet up with some other guys who have these trucks-- no better way to learn! I'm around Indyuke -- would be great to compare trucks and help me learn more about them.

Adam

[72 Super]

Welcome to the board from Maryland!

Good luck on your brakes and with your new Truck.

Ray