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Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 10:41 am
by RiverPatrol
…or the entire brake system. But at least the master. New master cylinders have been unavailable for a few years now, and now it seems that the rebuild kits for them have dried up as well. So now we and new Patrol acquirers are in a predicament. Wheel cylinders are plentiful but they don't do any good without a master cylinder.

When the lack of availability of points became a stopping point for keeping out Patrols running I went to Pertronics and had them build an electronic ignition kit for the water protect distributors. Problem solved. It's a drop-in kit, no modifications necessary. We need a similar solution now for the master cylinder.

One path that might work is to upgrade to a dual master. Not necessarily going whole hog with a booster, just a replacement for the original master cylinder. These folks have a dual master already modified to bolt on to the firewall: http://datsunpartsllc.com/cart/index.php?p=product&id=164&parent=11 . I know a couple of people that have used them. This path would obviously require a little bit of brake line creation off the master, and perhaps a proportioning valve? I've read where the master cylinder does the proportioning, but I've also heard that a proportioning valve is needed. That's the kind of stuff that we need a quick, down and dirty, streamlined 'How to' for. We have new members that come here looking for a simple solution to their brakes on the Patrol they just purchased, let's help them out. And us as well...

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 1:51 pm
by bosque
I seem to be full of bad ideas and here is another one..........how 'bout finding/making these? Measurements can be had......?
Image

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 2:21 pm
by Coyote Patrol
I will do some research on this. I have found a master cylinder off a Volvo that looks promising. I'm at work right now, can someone get me the measurement from center to center of the mounting holes on the Patrol cylinder?

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 2:26 pm
by Esteban
bosque wrote:I seem to be full of bad ideas and here is another one..........how 'bout finding/making these? Measurements can be had......?


I've always thought that in most cases, the cylinder will be in such a bad shape, that it doesn't make sense to repair it. Or, you'll have to sleeve it to make it work. Costs start adding up quickly. But then, there are many that just want to have the original one, so maybe your idea can work.

By the way, the Wilwood master cylinder at their website is substantially cheaper, so please take note:
http://www.wilwood.com/MasterCylinders/ ... o=260-8794

For me, what started as just another mechanical improvement, with my Bendix Hydrovac power booster decades ago, keeping the original single circuit master cylinder, evolved to a dual circuit Ford master cylinder and behind it a Master Vac from a Datsun pickup. Partly because the original master cylinder (actually the 2nd one) was beyond repair, and because I had the Master Vac out of my other totaled Patrol. I'm not a purist in this department, and for me function is more important that being period correct.

I chose the Ford master cylinder for a number of reasons: has the same I.D., easy to hook up the lines at the same side, I was moving to the States and parts would be easier to get, etc. Ten years after, I'm really happy that I opted this route.

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 2:43 pm
by Esteban
2869ral wrote:I will do some research on this. I have found a master cylinder off a Volvo that looks promising. I'm at work right now, can someone get me the measurement from center to center of the mounting holes on the Patrol cylinder?


Ron, I was looking at the 1965 Patrol Service Manual, that has some nice diagrams and one for the master cylinder with measurements. It looks that this distance is [edit] 65mm (2-9/16").

The Wildood cylinder that RiverPatrol posted, is 57.2mm (2-1/4") (will require cutting slotting the holes with a hack saw)

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 2:45 pm
by bosque
2869ral wrote:I will do some research on this. I have found a master cylinder off a Volvo that looks promising. I'm at work right now, can someone get me the measurement from center to center of the mounting holes on the Patrol cylinder?

2 9/16" OC
I think stopping trumps originality too......and stopping better than stock is damn smart. Just want to see all the options/possibilities.
68 mm = 2.677165354

Re: Someone should do a 'How to' on the brake master

PostPosted: Tue Nov 12, 2013 7:27 pm
by mdawg4x4
bosque wrote:
2869ral wrote:I will do some research on this. I have found a master cylinder off a Volvo that looks promising. I'm at work right now, can someone get me the measurement from center to center of the mounting holes on the Patrol cylinder?

2 9/16" OC
I think stopping trumps originality too......and stopping better than stock is damn smart. Just want to see all the options/possibilities.
68 mm = 2.677165354


^^What he said about stopping!

Re: Someone should do a 'How to' on the brake master

PostPosted: Wed Nov 13, 2013 9:46 am
by RiverPatrol
Esteban wrote:
2869ral wrote:I will do some research on this. I have found a master cylinder off a Volvo that looks promising. I'm at work right now, can someone get me the measurement from center to center of the mounting holes on the Patrol cylinder?


Ron, I was looking at the 1965 Patrol Service Manual, that has some nice diagrams and one for the master cylinder with measurements. It looks that this distance is [edit] 65mm (2-9/16").

The Wildood cylinder that RiverPatrol posted, is 57.2mm (2-1/4") (will require cutting slotting the holes with a hack saw)


The master cylinder that I posted from Datsun Parts is the Wilwood master that has already been modified to bolt right up to the firewall. If you buy the Wilwood master, it needs to be modified.

Re: Someone should do a 'How to' on the brake master

PostPosted: Wed Nov 13, 2013 2:26 pm
by antiquecyles
I appreciate everyone's help on my issue. I apologize for stirring the pot but it would appear it was just a matter of time.

I have a pending Paypal invoice from Schulderm (ebay) for a rebuild kit but before I pay I want to be sure it will work.
He will sell me the rebuild kit but without the piston.

When I took my Master Cylinder apart everything looks decent except the bushing on the piston is worn. It looks like it is built into the piston. If the rebuild kit I purchase doesn't come with the piston does it mean that this bushing isn't replaced?

The kit would be a waste. At 80 bucks, I can't see the value.

Does anyone know if the kit includes the piston bushing? (I wrote Schulderm but haven't heard back yet)

I am considering sending the master and all cylinders out and having them rebuilt....?

Thanks,
Kris

Re: Someone should do a 'How to' on the brake master

PostPosted: Wed Nov 13, 2013 2:38 pm
by moore_rb
RiverPatrol wrote:One path that might work is to upgrade to a dual master. Not necessarily going whole hog with a booster, just a replacement for the original master cylinder. These folks have a dual master already modified to bolt on to the firewall: http://datsunpartsllc.com/cart/index.php?p=product&id=164&parent=11 . I know a couple of people that have used them. This path would obviously require a little bit of brake line creation off the master, and perhaps a proportioning valve? I've read where the master cylinder does the proportioning, but I've also heard that a proportioning valve is needed. That's the kind of stuff that we need a quick, down and dirty, streamlined 'How to' for. We have new members that come here looking for a simple solution to their brakes on the Patrol they just purchased, let's help them out. And us as well...


The Wilwood unit does balanced 50/50 internal proportioning between the front and rear reservoirs, and each reservoir sources its own outlet; so the decision of whether or not to add a proportioning valve is a judgement-call. You can make the Willwood piece work with a P-valve, or without one.

The stock brake layout on the 60 Patrol did not include a P-valve. All the brake line pressure comes from a single master cylinder reservoir, through a single outlet, and is then split between front and rear by a passive (non proportioning) T-fitting. Proportioning duty is handled by the fact that there are twice as many wheel cylinders up front as in the rear; so the net pressure applied to each cylinder is less up front, allowing the rear wheels to lock up first if you stand hard on the brake pedal.

Now, back to that Wilwood master cylinder - It has two reservoirs, so there are a number of ways you could successfully plumb it in. I have broken some of these methods down according to some specific scenarios:

Scenario One would allow you to install the Wilwood master directly to the patrol's single stock master cylinder outlet brake line - you would need to Tee the two outlets from the Wilwood part together, and then hook the single Patrol outlet line in into the T fitting:

outlet 1 outlet 2
|_____Tee_____|
|
|
original patrol brake line


This is the "quickest, easiest" way to restore your Patrol's operational brakes with the Wilwood piece, but it is in no way ideal, because you would be Tee-ing 2 outlets into one line, and then the stock Tee would just split the 1 line back into 2 to route the fluid to the axles... Also, this method preserves one very basic, inherent shortcoming in the 60 Patrol's original brake circuit design - if you lose pressure ANYWHERE in the system, then it affects the braking performance at ALL FOUR corners.

So, One better way to hook up the Willwood master would be to take advantage of the dual reservoirs, and eliminate the factory Tee (the one on the frame directly below the master cylinder), and run the outlet from the rear reservoir to the stock Tee on the rear axle, and to run the front outlet to the stock Tee on the front axle. The advantage of this method is that now each axle has its own dedicated pressure circuit, so if one reservoir (or wheel cylinder) starts leaking, it will not disable the brakes on BOTH axles - obviously, this is MUCH better from a safety perspective. This method also still preserves the same stock front to rear brake proportioning bias inherent to the original Nissan design.

Regarding the topic of using a Proportioning valve, versus not using one- The decision whether to use a P-valve or not is really only relevant if you want the modify your Patrol's default front to rear brake bias; maybe due to a power brake or disk brake conversion, or due to the installation of larger off-road tires, etc...

But, the reader's digest summary is that if you want to use the Willwood Master cylinder, you do not NEED to add a P-valve. You only need to decide whether you want to install a 2nd Tee (not recommended) or eliminate the existing tee and plumb it front to front, and rear to rear (highly recommended)

If I have time before dark when I get home today, I'll test the master cylinder in the Deathtrap Patrol. If it turns out to be shot, then I will probably order the Wilwood cylinder and plumb it in using the "front to front, rear to rear" method I outlined above, and I will be sure to post a step by step how-to...