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411 Front Disc brakes


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Well, I picked up the RL411 disc brake parts from pl521sss. Now I just need a Master Cylinder and some new soft brake lines and I think I'm in business!

 

Anybody have an RL411 disc brake master cylinder in serviceable condition?

 

See my entries in Brakes for a fully compatible new Nissanproduced brake master cylinder suitable for the RL411 even though it is listed as for the 1500 cc roadster with the warning that the hard line outlet is "on the wrong side" which makes it an exact match for the RL411 sedan.  It has a 1500cc sized fluid receptical which is slightly smaller that the stock RL411 master cylinder, but the recepticals are interchangable.  In any case I chose to go with the slightly smaller fluid receptical and have had no regrets.  If you want to Motocross or road race you might want to swap for the larger capacity "tank"but it's your choice.  By the way, in the same forum read my input on a solid brass brake light sensor as opposed to the "normal" stamped steel bodied switch.  Currently produced brake light sender switches have an excessive braze joint on the tapped end which prevents proper seating and sealing of the install.  In plain English, it cannot seal and will leak fluid all over your firewall.  The solid brass replacement seats and seals properly.  However, and this is the catch, you cannot use the standard brake switch socket, or any standard socket to install it.  The brass unit has sharp 120 decree corners, not the rounded off corners used in any available socket which have rounded corners to avoid stress concentration.  Use a common crescent wrench to install it and drive away "Happy!"  I did,

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Hi Mike,

Thanks for the info. That #1560 MC on Datsunparts.com is listed at $374! WTF? I wonder why I see it listed elsewhere on the web for around $115-$120. Are those MCs available from the dealer?

 

In any case, it's just a single bore MC. I was thinking along the lines of upgrading to a tandem bore MC to separate the front and rear brake circuits. I assumed that the RL used a tandem bore. Is there any reasont o move from a PL to an RL MC? Is there a bore-size difference?

 

As for brake light switches, I've never been a fan of line pressure switches. In my other cars I've bypassed them and used a pedal-activated switch instead. They are simpler, more reliable and you can mount them to come on with the slightest pedal pressure. I like the idea of my brake lights switching on sooner rather than later.

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The RL411 brake master cylinder is not available through the Nissan network.  Some, but not many, dealers can arrange to have your old one rebuilt but that will last a year at best.  The RL411 uses a single bore with a slightly larger reservoir, the 1500 roadster reservoir is smaller but works just fine [i have it on my RL411].  If you are worried, the old larger reservoir can be swapped over .  The Datsunparts is a genuine Nissan part and comes in a Nissan box, plain vanilla not the old red white and blue early parts box.

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Hi Jesse, Congrats on your 411 you can easily and afford ably mount a 620 Master. Ive even mounted a B210 master here is a link to how 'I did mine on page 1. Hope this helps keep that 411 on the road !!

 

http://community.ratsun.net/topic/49846-mklotz-411-disc-brake-conversion-project/

Hey, that's a good alternative. I like the idea of a twin bore MC, and since 620s where Disc/Drum it would definitely be balanced and move enough fluid. I made a pushrod for my race car the same way you did, btw. I need to get some new brake lines and then I'll get these discs installed.

 

~Jesse

 

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  • 2 weeks later...

yes, as most folks are saying I think you can use a 311 master cylinder, very similar.  Might have to rebend your lines.  Let us know how this is going.  I  had this done to my PL 410 many years ago to autocross race. I might have some spare used brake parts. 

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yes, as most folks are saying I think you can use a 311 master cylinder, very similar.  Might have to rebend your lines.  Let us know how this is going.  I  had this done to my PL 410 many years ago to autocross race. I might have some spare used brake parts. 

 

Hi Tana,

 

Thanks, Do you have any spare hardware parts: springs, clips, bolts and pins?

 

I'm wondering if I will need to change the master cylinder. My current one is fine, but I was thinking that I would have to switch it out for one that's balanced for Disc/Drum, but the 311 mc is a single bore like the 411 mc.

 

I have a brake cylinder rebuild kit and new 311 brake hoses on the way. I want to clean up the replacement parts and paint them before I install them, but hopefully I'll be able to get started on this weekend.

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Hey, Jesse,

 

I am running the 620 master in my '66 with '67 front discs. My M/C came with a pushrod, which I used with no problems. 

 

I used the stock line from the union block to the M/C, with a new metric fitting flared onto it, and a different bend at the end to hit the right spot on the M/C. 

 

I removed the rear line from the union block and plugged the outlet on the block. I then ran a new, short length of line from the M/C to a union fitting to the line to the rear brakes.

 

Been driving it for a few years with no leaks or other issues. I can take pics if you want.

 

It was a hassle to rebend, flare and install the lines with the engine in place, but not nearly as bad as installing a new clutch line with the engine in place!

 

Jesse.

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I've made plenty of hardline for other cars. It's not the most fun thing to do, but I've had success with a good flaring tool, some various bending tools and ALOT of patience. 

 

I ordered new caliper cylinders, caliper rebuild kits, brake pads, wheel bearing and seals from Rock Auto. I found a good set of brake hoses off Ebay. The rotors I have look decent, but I'm curious... I can't find new ones listed anywhere. Are they the same as 311 rotors or something else? They aren't the same as 510, I know that.

 

~Jesse

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I finally started installing the RL disc brakes. I sandblasted and painted everything. This was the fist time Ive ever used a sang blaster. Its fun! I used grey Por15 on most of the parts and VHT caliper pain on the calipers. I rebuilt the calipers and pistons with parts from Rockauto. I reused the wheel bearings that came with the set up since they seemed pretty good still. I used Timken 1188 seals that are narrower than the originals but I think will work. I found 311 brake hoses on Ebay for about $45 and they fit perfectly.  I only installed the drivers side, I'll do the passenger side tomorrow. I bled the system and have a really nice hard pedal. The only problem is the hub diameter at the wheel is larger than before so the .25" wheel spacer I was using doesn't fit, so I need to find new spacers or spend several awful hours filing the center on the  ones I have.

 

Here are some pics:

 

IMAGE_56.jpg

 

IMAGE_59.jpg

 

IMAGE_60.jpg

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I finished up the disc install and took the car for a quick spin last night at around midnight. The pedal feels good but the front-/rear balance is off. It's fairly easy to get the rear wheels to lock up under quick braking, so I will need to install a proportioning valve.

 

I think RL411s have an inline valve on the firewall maybe? It would be great to find a factory valve, but if not I'll get an adjustable one.

 

I'll drive it some more later today and then check to see if the front brakes are dragging at all. If they are that means that the stock PL411 master cylinder has a residual valve that keeps a small amount of line pressure, which is good for drum brakes but not good for discs. If that is the case I'll probably go with a 620 master, but otherwise the stock master will do just fine.

 

Anybody know how the RLs or Roadsters have their brakes balanced front to rear? Is there a prop valve somewhere in the system?

 

~Jesse

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Jesse,

 

You don't include a pic of how you set up your lines, but here is what I did (with a 620 disc/drum master cylinder) on my '66 with '67 front discs. If I didn't have the engine in the car at the time, I would have routed the lines more cleanly, but this is what I could manage with the space I had. 

 

I should note that where I say "Brake Master (front)" I mean the reservoir FOR the front, which is actually towards the back of the car, and likewise for "Brake Master (back)". 

 

Jesse.

 

411_brakes_front_disc_on_drum_car.jpg

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  • 2 months later...

So I bought a dual bore master cylinder for a 620 from Rockauto (despite my grudge against them). I bought the Centric one (#13042102) since it has the bleeder screws on the right side, away from the clutch master. It fits perefctly except that the forward reservoir is a liitle close to the air cleaner housing. Also, the brake pedal pushrod needed to be 1/4" longer to make up for the ne new mc not protruding as far intot he cabin as the stock 411 mc. I ended up buying a couple of parts from Pegasus Racing to make a new pushrod. I bougth a steel clevis and a 7" Girling pushrod that I cut down by 3". It ended up being a pretty nice pushrod assembly nearly identical tot he stock one but with built-in adjustability.

 

IMG_7372.JPG

 

Here it is assembled:

 

IMG_7373.JPG

 

And installed on the new master cylinder (top) with the old stock 411 master cylinder for comparison:

 

IMG_7374.JPG

 

 

Then I made up some new brake lines. I'm running the front circuit from the master cylinder to the 4-way junction on the firewall. I'm going to plug the outlet at this juction that goes tot eh rear brakes. Then I'll run use a female/female coupling to tie the existing rear brake line to this short intermediate line which will run tot he rear circuit on the master cylinder.

 

Here are my two new lines on top and the old line on the bottom.

 

IMG_7375.JPG

 

I got everything installed and bled the master cylinder after I got it all hooked up. Tomorrow I'll bleed the rest of the system and take it for a spin!

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  • 3 weeks later...

I installed the 620 master cylinder and got the car running. The one small issue was finding a 3/8" plug for the unused port on the  4-way junction. The ones I could find didn't have enough threads to seat properly and would leak. I finally found one with literally an extra mm of threads from Speedway Motors. I installed that and took the car for a spin. I still need to do a full bleed of the brakes, since I can tell there is air in the system still. I'll get my GF to pump the brake pedal for me this weekend...

 

The 620 MC fits really well, except the foremost reservoir sits very close to the air cleaner.

 

mastercylinder1b.jpg

 

mastercylinder2.jpg

 

 

mastercylinder4.jpg

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