Jump to content

L320 Disc brake conversion


Hoffinator

Recommended Posts

Here is the parts/tools list for the Disc brake conversion. I'll post the pics as soon as I have the photo bucket thing done. This conversion was done using the adapters the guy on Ebay has for sale.

 

Parts:

Disc brake adapters (ebay)

Calipers - 97 Nissan Hardbody 4x4 (Rock Auto, $10 core)

Hydraulic lines for calipers (these are banjo style) (Napa)

Rotors - 2002 Isuzu Rodeo 2wd (Napa)

Master Cylinder - 1979 Datsun 620 (rock auto)

Wilwood proportioning valve (amazon.com)

2 bolts for the banjo connections at the calipers (wrecking yard)

4 12mm 1.25mm (fine thread) bolts for caliper brackets (wrecking yard)

16 feet of 3/16 brake line, if you are going to replace all the front brake lines.

4 metric to sae brake line adapters (napa) (Eaton 1443)

1 3/16 to 3/16 brake line adapter (if you are using old rear brake line)

5/16" 2.5" long bolt/washer/nut (for mounting proportioning valve)

3/8" grade 8 bolt 3" long with 2 nuts and 1 lock washer (for new push rod)

Clevis pin/yoke (don't know if that the proper terminology or not, but is also for the new push rod)

A couple small pieces of 1/8 or 1/16 steel

one 12mm washer

 

The 12mm bolts for the caliper brackets are very difficult to find at the store. The stock ones from the Hardbody are too long. I found mine on an 80s 280zx along with the banjo bolts.

You just have to hunt around in the wrecking yard for the right size, there are lots of them out there. Honda uses the 12mm on some of their caliper brackets, so check those as well. Hey, who doesn't like going to the wrecking yard? I forgot the exact length, so I'll add that later.

 

I'll post the step by step next and then the pics.

Link to comment
  • Replies 27
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Always good to do the write ups. Even if no one speaks up today, someone may come along tomorrow and need to see exactly what you've posted. Half the time, I post the stuff just so I can refer back to it myself :)

Link to comment

If the rear shoes were taken off and put back on....they may have been put on wrong. I'm pretty sure there's a front shoe and a back shoe. If I remember right, the drum brakes are a self actuating style and if the shoes go in wrong, they will grab.

Link to comment

If the rear shoes were taken off and put back on....they may have been put on wrong. I'm pretty sure there's a front shoe and a back shoe. If I remember right, the drum brakes are a self actuating style and if the shoes go in wrong, they will grab.

 

You remember correctly, there is a front and back brake shoe.

 

I see you listed 4 metric to sae brake line adapters, I usually just buy the 3/16 size brake line and get some with metric fittings and some with sae, then when I bend and flare the lines I just put the metric fittings where I need them and the same with the SAE. Does that make sense, wish I had a pic. Any way, I like to eliminate the extra connections. Z

 

 

 

Link to comment

You remember correctly, there is a front and back brake shoe.

 

I see you listed 4 metric to sae brake line adapters, I usually just buy the 3/16 size brake line and get some with metric fittings and some with sae, then when I bend and flare the lines I just put the metric fittings where I need them and the same with the SAE. Does that make sense, wish I had a pic. Any way, I like to eliminate the extra connections. Z

 

 

 

 

Yea, I thought about doing that, but I wanted to minimize the double flares I had to make. They aren't as good as the factory flares.

Link to comment

Well, I've gone through the entire brake system again. I now have two proportional valves in series on the rear lines. Rear brakes still lock up. I didn't brake into the rear brakes, but they are adjusted correctly. I have the 77 280Z master cylinder on order, and I'm going to try that. If that doesn't solve it, I gotta go back to the drums. That wold be lame.

 

If anyone, which it sounds like a lot of you have, has done the conversion; it would be great to have the whole write-up. I can't find any complete write-ups on the forums, which is why I was doing this one. If there is a complete write-up, please point me in that direction.

 

Thanks

Link to comment

Yea, I thought about doing that, but I wanted to minimize the double flares I had to make. They aren't as good as the factory flares.

 

You just need to have a quality flaring set. Use a little oil or grease when flaring. Not that you need my advice.

 

Can't wait for the pics. I redid my stock brakes and I have been thinking about

 

I just looked at my post from when I redid the stock brakes and added a dual master but I didn't take any photos of modifying the brake lines to be metric on one side and sae on the other.

 

Oh well.

 

 

 

 

Link to comment

but I wanted to minimize the double flares I had to make. They aren't as good as the factory flares.

 

Then you need to buy a quality tool to do the job.

 

If you really wanted to minimize the number of flares you needed to make, then you would inspect your rear brakes and correct the problem before installing a second valve. Most of those valves have a 57% reduction in line pressure. With two valves inline you are only getting 19% of the master cylinder output pressure. There is no way this is a pressure valve problem.

 

A 57% reduction is more than enough IF the rest of the system is configured properly and in proper working condition.

 

When are the rear brakes locking up? Every time you apply the brake pedal or gradually after driving and you have applied the pedal several times? Is it just one side locking up?

 

You say that the rear brakes are adjusted correctly. You CAN'T know if they are adjusted correctly if you dont know their condition at all. Are they metal to metal(you dont know). Are the shoes backwards(again, you dont know). Are the cylinders working correctly(once again).

 

You said that you installed a 79 620 master cylinder. How did you plumb the lines? Front reservoir to front brakes and back res to back brakes?

 

NOW, with all that said, here is the two things that i think you need to look into before anything else. 1. how the master cylinder is plumbed in. And 2. the rear brakes.

 

Something tells me that the master cylinder is plumbed in backwards.

 

Good Luck

Link to comment

Then you need to buy a quality tool to do the job.

 

If you really wanted to minimize the number of flares you needed to make, then you would inspect your rear brakes and correct the problem before installing a second valve. Most of those valves have a 57% reduction in line pressure. With two valves inline you are only getting 19% of the master cylinder output pressure. There is no way this is a pressure valve problem.

 

A 57% reduction is more than enough IF the rest of the system is configured properly and in proper working condition.

 

When are the rear brakes locking up? Every time you apply the brake pedal or gradually after driving and you have applied the pedal several times? Is it just one side locking up?

 

You say that the rear brakes are adjusted correctly. You CAN'T know if they are adjusted correctly if you dont know their condition at all. Are they metal to metal(you dont know). Are the shoes backwards(again, you dont know). Are the cylinders working correctly(once again).

 

You said that you installed a 79 620 master cylinder. How did you plumb the lines? Front reservoir to front brakes and back res to back brakes?

 

NOW, with all that said, here is the two things that i think you need to look into before anything else. 1. how the master cylinder is plumbed in. And 2. the rear brakes.

 

Something tells me that the master cylinder is plumbed in backwards.

 

Good Luck

 

 

Thanks for the help and the unnecessary criticism.

 

You know a really good flare tool is $350, that's a little too much for 4 flares. The adapters work great, and the cheap Napa flare tool got the job done well enough.

 

The MC was not marked front/back, so I had to guess. The large reservoir is usually the front, so that's how I plumbed it. I thought the same thing you did, and switched the lines already. That didn't do any good. Since having the lines swapped should have had some effect, I am thinking the MC is the problem. I have a new 280Z MC that I'm going to try along with a new adjustable push rod (thanks for the suggestion Flatcat).

 

Obviously I'm not planning to keep both proportioning valves on. I just have the two for testing the system. The second one went in without adding more flares. I have a coupler where the new lines tie into the rear, so I just put in in place. Easy.

 

I actually do know the status of my rear brakes. As I said before, I went back through the entire system. I'm getting desperate, so I'm going to check them again, Plus, you were so worked up about them, how can I ignore it. I don't want to switch back to drums, but I don't want to miss another cruize-in either. If one of these things doesn't work, I gotta switch back and try again in the fall.

 

I appreciate the help.

Link to comment

I didn't see where you checked the back either. yello said the same thing I would have said since it didn't seem like you wanted to be bothered with the rears. I still would like to hear if the shoes are in the correct position. Since you never gave a response to that suggestion previously, I wasn't going to bother giving anymore input.

 

If you want to drive the truck....you can block off the rear circuit completely and see how it drives. The fronts do 80% of the braking.....you probably won't even miss the rear brakes for now. Beats parking it until the fall :)

Link to comment

Well, I've gone through the entire brake system again. I now have two proportional valves in series on the rear lines. Rear brakes still lock up. I didn't brake into the rear brakes, but they are adjusted correctly. I have the 77 280Z master cylinder on order, and I'm going to try that. If that doesn't solve it, I gotta go back to the drums. That wold be lame.

 

If anyone, which it sounds like a lot of you have, has done the conversion; it would be great to have the whole write-up. I can't find any complete write-ups on the forums, which is why I was doing this one. If there is a complete write-up, please point me in that direction.

 

Thanks

 

 

Well according to the fourth sentence in this post. You did NOT look at them.

 

Thanks for the help and the unnecessary criticism.

 

You know a really good flare tool is $350, that's a little too much for 4 flares. The adapters work great, and the cheap Napa flare tool got the job done well enough.

 

The MC was not marked front/back, so I had to guess. The large reservoir is usually the front, so that's how I plumbed it. I thought the same thing you did, and switched the lines already. That didn't do any good. Since having the lines swapped should have had some effect, I am thinking the MC is the problem. I have a new 280Z MC that I'm going to try along with a new adjustable push rod (thanks for the suggestion Flatcat).

 

Obviously I'm not planning to keep both proportioning valves on. I just have the two for testing the system. The second one went in without adding more flares. I have a coupler where the new lines tie into the rear, so I just put in in place. Easy.

 

I actually do know the status of my rear brakes. As I said before, I went back through the entire system. I'm getting desperate, so I'm going to check them again, Plus, you were so worked up about them, how can I ignore it. I don't want to switch back to drums, but I don't want to miss another cruize-in either. If one of these things doesn't work, I gotta switch back and try again in the fall.

 

I appreciate the help.

 

Master cylinders are almost never marked, if you dont know where things go then you should not be touching a brake system until you learn.

 

How about a picture of the front caliper system installed? Maybe somebody sees a problem that helps you fix it.

 

And what is so difficult about answering ALL of the questions that have been asked, we are asking these questions for a reason. That reason happens to be to help the guy that is asking for help.

 

So, i am done with the help until you are ready to step up and answer some questions to try to help yourself. Call it criticism if you want. Remember that you are the one that wants help. And i happen to be ASE certified in brake systems, and have spent the last twenty years doing brakes professionally.

 

Have a good day.

Link to comment

Brakes are one of the easiest things to do on a car...

Brakes are one of the easiest things to fuck up on a car.

 

With how huge the liability is with the braking system,

you really need to know what you're doing.

Your life, your trucks life, and anyone else's life is on the line here.

If you skip a step, and go wreck, it's on you.

Don't take the chance.

 

A brake inspection inspects every component of the braking system.

Listen to what Klotz and Yello have to say.

Klotz is the reason for why you were able to buy disc brake adapters for your 320.

Yello has displayed more than enough work here in the forum, plus ASE certified in brakes.

Like it or not, it seems they know a little more than you, and are really just trying to help.

Just look at your rear brakes. Thats it. Your answer to whats wrong might just be back there.

But if you wanna keep throwing money away, let us know when you hit the road, so we can lock up the kids.

  • Like 1
Link to comment

Here is where I started, download the manuel

 

http://www.olddatsuns.com/620tech.htm

 

read manuel, then try something like this

 

http://community.rat.../page__hl__l320

 

refer to manuel if problems arise, if nothing else it may provide comic relief.

 

Don't get testy, you must be calm to fix your braking problem.

 

Take many pictures and post freely.

 

Just so everyone knows, I redid the stock brakes before doing the disc for this very reason.

 

It is sometimes helpful to get the stock setup working before trying to improve it.

 

FYI, I think the self energizing brakes are the front brakes, at least the brakes that have the different size shoes. The pictures are in the thread. Between that and the manual, all should become clear.

 

Truck still stops but must be adjusted regularly, mine that is.

 

Close eyes and concentrate.....let the Ratsun flow through you.....do not resist.

 

My flaring tool is the middle quality...around 100 dollars....worth every penny. But must be used right. This takes practice. Practice is cheap when brake lines can be cut into so many pieces.

 

Anything in this rant that does not apply to you or interest you....ignore.

 

Thinking positive thoughts, sending them to you. Only positive.

  • Like 1
Link to comment

It works! Seems like it was the pushrod. The first one I made was preloading the MC about 1/8". Seems weird that would have such a dramatic effect on the system. Now there is a lot of play on the proportional valve. Thanks Flatcat for the suggestion.

 

LOL, wow you guys are sensitive. I realize that Mike and Yellow are top notch in knowledge, there's no where I didn't listen to their advice. I checked everything they said to, including the rear brakes twice. It seemed most of the replies were more interested in criticizing rather than giving helpful suggestions, such as all the stuff about doing the flares. So weird.

 

Thanks again.

 

Good luck all.

Link to comment

Brakes are one of the easiest things to do on a car...

Brakes are one of the easiest things to fuck up on a car.

 

With how huge the liability is with the braking system,

you really need to know what you're doing.

Your life, your trucks life, and anyone else's life is on the line here.

If you skip a step, and go wreck, it's on you.

Don't take the chance.

 

A brake inspection inspects every component of the braking system.

Listen to what Klotz and Yello have to say.

Klotz is the reason for why you were able to buy disc brake adapters for your 320.

Yello has displayed more than enough work here in the forum, plus ASE certified in brakes.

Like it or not, it seems they know a little more than you, and are really just trying to help.

Just look at your rear brakes. Thats it. Your answer to whats wrong might just be back there.

But if you wanna keep throwing money away, let us know when you hit the road, so we can lock up the kids.

 

Yea Flat, I agree, they do know more than I do. That's why I'm asking for help. That's why I'm listening to everything they're saying. I don't get why so many replies are so critical. Thanks for your pushrod suggestion, that was the problem.

 

 

 

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.