Rear Drum and Toyota 4x4 front disc questions.

[mr_han_solo]

Hello,

I some different questions regarding the brakes.

On a lot of threads I have heard people say that the 240z stock rear drums are on par with any disc upgrade. They also mention some drum upgrades, but never specify what the exact upgrades are. I am looking into stainless steel lines and rear performance brake shoes. Is there anything else I need as far as a rear drum upgrade?

On my front brakes I am upgrading to the Toyota 4X4 breaks. I was actually looking at getting the vented ones. However, I read that I will need a machined spacer to correctly move the hub from the rotor for wheel clearance and matching bolts. The source of these were Modern Motorsports. However, I see that they no longer sell these. I was wondering if there was any other source for these spacers? If not how much of a performance hit will I be taking if I back down to the standard Toyota 4x4 brakes? I do plan on doing some auto crossing in this car.

The other brake upgrades I will be doing is the 15/16 master cylinder from a '79 280zx.

Hope someone can chime in so I can load up on some parts to get me started.

Thanks,

Han

[Miles]

1. Go back and read all of the stickies and FAQs on brake upgrades. If you actually read them you will see what a mistake you are about to make.

 

2. The 280ZX MC is NLA which you will learn about if you read the Brake Forum.

[mr_han_solo]

1. Go back and read all of the stickies and FAQs on brake upgrades. If you actually read them you will see what a mistake you are about to make.

 

2. The 280ZX MC is NLA which you will learn about if you read the Brake Forum.

 

I read the brake FAQ when I started researching the upgrades. I originally wanted to go with the Maxima rear disc conversion. However, I read the big disclaimer up front that said that the stock brakes were plenty adequate. Thus i decided to keep the rear drums.

 

However, I still wanted to do the front upgrade since. I saw that the 4x4 was essentially a bolt in and that the vented required a spacer. I just wanted to see if I could still get the spacer, and if the vented vs. non vented made much of a difference.

 

2. I dont understand what you mean about the 280ZX master. The brake FAQ says the following: "The stock master cylinder is really unsuitable for any 4 piston caliper upgrade. It works marginally for the Toyota 4 piston calipers, but really increases the pedal throw. A 79-81 280ZX master is a nice upgrade and is suggested by Modern Motorsports and Arizona Z Car when using their brake kits discussed above."

[Miles]

NLA = No Longer Available because  Nissan does not supply the 280ZX MC nor do the rebuilders.  Very old news here.

 

See Wilwood MC swap in the brake forum

 

BTW (By the Way) the vented Toyota front brakes with the stock drums will be unbalanced such that the rears won't be able to keep up with the vented brakes. Searching will explaine why.

 

Just put some Hawk HPS pads on the front and some quality shoes on the rear and maintain the brakes properly.

 

If you absolutely have to do a brake "upgrade" then put the Toyota non-vented calipers on and be done with it. And yes you will have to go to a larger volume MC (e.g. Willwood 1 inch)  with the this swap or the brake pedal will be too low.

[mr_han_solo]

I searched Advance Auto Parts website and found this master cylinders for a 1979 280zx:

 

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_master-cylinder--remanufactured-cardone_5804256-p#.UrcLnV_tbRU.gmail

 

http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/product_brake-master-cylinder-wagner_26946112-p#.UrcMQhpYaQI.gmail

 

Are these not the correct master cylinders?

[seattlejester]

Well, glad you took a look at the FAQ. 

 

Miles is correct, a lot of this is floating out there, it may be a lot to look up, but quite a few of the topics have been covered in the last few months, the master cylinder question actually pops up quite often.

 

Essentially the 79-81 15/16th inch master cylinder with the split reservoirs are NLA. A lot of parts stores will list that they have it, but when you go to order them, they will inform you they don't have any. When the store I went to called cardone for the final word, they said they did not have any cores to rebuild them. So unless someone turned in a bunch of cores or someone decided to do a run of the 15/16 master cylinder for datsuns/nissans since the last time the question popped up, it is still very unlikely that they have any. Some people have gotten lucky, but many more have found that it is extremely difficult to find a re manufactured one. The current option is to find one used and send it in to get rebuilt, or do as miles suggests and go slightly bigger to a wilwood 1 inch which will require slight modifications listed in the forum.

 

Yes, the rear disc brakes are not much of an upgrade. It can be easier to service, and worst comes to worst, the caliper will keep your wheel on if hub decides to let go.

The general consensus is better compound shoes combined with a resurfaced aluminum drum is perfectly acceptable. You can replace the wheel cylinder and springs and make sure to set the clearance for smooth operation and you will have very decent stopping power from the rear.

 

If autocrossing is the racing of choice, you won't see very much of a benefit from vented front brakes. With a typical autocross run running less then two minutes, with a cool down time in between each run, in a very light car, and speeds rarely exceeding 60mph, you probably won't get the fronts hot enough to take advantage of the vented rotors. If you were doing track driving or other such activities where you will be going much faster and repeatedly slowing down, then the vents will help dissipate some of the heat built up from repeated braking. 

 

You are correct that the vented setup will require a machined spacer to push the wheel out. This will mean you will be running different offsets front and back if memory serves, which can be troublesome if you are running directional tires.

 

Downfalls of the traditional 4x4 solid rotor swap is that the secondary pistons are a slightly smaller diameter. Honestly if you are overheating the rotors to the point that you need the vented rotors, you may want to look into a serious track oriented setup with wilwoods all around.

[mr_han_solo]

Miles and SeattleJester the two of you have been tons of help. I went ahead and pulled the trigger on the Master Cylinder. It shows that the item has shipped, so I will just have to see if it is the 15-16 when it gets here, I'm really hoping it is.

 

I also went ahead and bought new wheel cylinders, shoes and stainless steel lines. On the front I bought the Toyota 4x4 (non vented) calipers. I did read a post where a guy was on a run with a Z-group and overheated his front breaks (with the 4x4 setup). He said "If you do enough research on this, you'll find that the problem is that this swap upsets the balance and the fronts are doing almost all of the braking. There is no easy way to fix this, and an adjustable proportioning valve is not the answer. The purpose of these are to reduce pressure to the rears, while an increase is really needed." After reading what you said, I feel that perhaps he should have upgraded to a more track oriented setup, however, this may be something I have to keep my eye on.

[BluDestiny]

What you read, and I think the point they were trying to make is that you are now going to have an unproportioned brake set up. I'd take a stock proportioned set up over yours any day and I'd probably be able to outbrake you. Your front will probably lock up a lot easier now, which isn't a good thing.

 

That segment you quoted even says that a proportioning valve can't make it back to normal.

 

I'd do a rear disc setup for the reasons Seattlejester listed, like the hub not falling off and the ease of service. Plus it looks better. But if I wanted a serious track setup id go with the AZC track setup

[Nigel]

 

 

You are correct that the vented setup will require a machined spacer to push the wheel out. This will mean you will be running different offsets front and back if memory serves, which can be troublesome if you are running directionaltires.

 

The machined spacer is to provide the correct offset for the vented rotor to center it in the caliper. Caliper clearance to the wheel is a separate issue. Most wheels will clear the 4x4 caliper just fine.

 

He said "If you do enough research on this, you'll find that the problem is that this swap upsets the balance and the fronts are doing almost all of the braking. There is no easy way to fix this, and an adjustable proportioning valve is not the answer. The purpose of these are to reduce pressure to the rears, while an increase is really needed." 

 

This is a little misleading. An adjustable valve will allow you to dial in up to full rear line pressure with no drop off. This is likely what you'll need with the the 4x4 and drum combo. However, even that may not be enough. But it would be a significant improvement over having the stock proportioning valve. That being the case, you could simply remove the stock proportioning valve and accomplish the same thing. However, if you ever plan to make further upgrades to the brakes, it would be worthwhile installing an adjustable valve now.

 

Nigel

[seattlejester]

My memory does not serve me well, I think I am referring to the AZC brakes. 

 

Nigel is on the money.