- Joined
- Jul 16, 2009
- Location
- Monterey/Falun
So as stated above I was having massive issues with the brake system. Due to the non leaker brake junction block being unobtanium at this point i decided to convert the brake system to a more traditional style split system. The first thing i did was remove the brake octopus and gutted it removing all of the springs and pistons. I tapped the internal portion of the octopus to 1/8th npt and installed 2 pipe plugs on each side. I tapped the brake failure circuit for a 1/4 inch plug and installed that as well.
then it was time to find some abs caliper....... Well those are basically unobtanium at this point so i did some research and found the datsun guys use these calipers and they will use the stock dual circuit calipers in single circuit form. The was a guy by the name Breck Meyer that used to made a bolt on manifold for these brakes which converted them to a single line. I could not find these parts either. so i just went ahead and found some video links from the datsun forums to cross drill the inside caliper half to convert it to a single circuit caliper.
I watched the video several times and basically the gist of it is to replicate the one hole in the bore marked number 1 into the number 2 bore so they meet. I started by making a little indentation with a carbide bit and got some long drill bits from the hardware store to make my life easier.
I started with a 1/4 inch drill bit and then went with a 5/16 drill bit. It went really well and i was able to get through the caliper in no time.
I installed a plug in the upper port of the brake caliper and installed a single line up front. I installed my freshly plugged brake octopus and plugged 2 ports on it. I ran the line from the front of the master cylinder to the rear of the junction block and the rear master cylinder port to the front and went ahead and threw some of the ipd aftermarket stainless lines on it. Also the aftermarket lines are not worth the hassle just buy lines from pelican parts for a porsche, they are the same as the ipd branded lines and about half the price. At this point i attempted to bleed the brakes and now came the first issue. The rear brakes bled fine, front brakes not so much. I had already had 3 master cylinders on the car and they all leaked which was fantastic but number 4 did not leak. However i was getting 0 volume out of the front calipers. I tried another one of the master cylinders that leaked and still the same thing. At this point i was getting a bit frustrated as far as after trying to simplify the brake system i now has a setup that did not work at all. I attributed this to it being a step bore master cylinder and the fact that the 240s have a pretty confusing brake system to begin with. So i decided to scrap the idea of using the volvo master cylinder and went to the auto parts store and got a sn95 cobra master cylinder. I cut the line going to the rear and got some brake line fittings for 3/16 m12x1.0 bubble flare and put the brake system back together. after that the brakes bled almost immediately and i had a nice hard pedal. Funny enough these are probably the best feeling 240 brakes ive ever had on a 240. I think the proportioning valves in the rear however have some garbage in them because the rear brakes seem to not be grabbing as hard as they should. for this i think my plan of attack is going to be to delete the rear proportioning valves and put a adjustable one up front. They are pretty cheap so i will probably get 2 just to have a backup. The whole goal of this brake system debacle was to delete some of the stuff that is becoming very hard to find and get a system that is simplified and ready for bigger brakes if i ever decide to swap to different wheels and tires.
then it was time to find some abs caliper....... Well those are basically unobtanium at this point so i did some research and found the datsun guys use these calipers and they will use the stock dual circuit calipers in single circuit form. The was a guy by the name Breck Meyer that used to made a bolt on manifold for these brakes which converted them to a single line. I could not find these parts either. so i just went ahead and found some video links from the datsun forums to cross drill the inside caliper half to convert it to a single circuit caliper.
I watched the video several times and basically the gist of it is to replicate the one hole in the bore marked number 1 into the number 2 bore so they meet. I started by making a little indentation with a carbide bit and got some long drill bits from the hardware store to make my life easier.
I started with a 1/4 inch drill bit and then went with a 5/16 drill bit. It went really well and i was able to get through the caliper in no time.
I installed a plug in the upper port of the brake caliper and installed a single line up front. I installed my freshly plugged brake octopus and plugged 2 ports on it. I ran the line from the front of the master cylinder to the rear of the junction block and the rear master cylinder port to the front and went ahead and threw some of the ipd aftermarket stainless lines on it. Also the aftermarket lines are not worth the hassle just buy lines from pelican parts for a porsche, they are the same as the ipd branded lines and about half the price. At this point i attempted to bleed the brakes and now came the first issue. The rear brakes bled fine, front brakes not so much. I had already had 3 master cylinders on the car and they all leaked which was fantastic but number 4 did not leak. However i was getting 0 volume out of the front calipers. I tried another one of the master cylinders that leaked and still the same thing. At this point i was getting a bit frustrated as far as after trying to simplify the brake system i now has a setup that did not work at all. I attributed this to it being a step bore master cylinder and the fact that the 240s have a pretty confusing brake system to begin with. So i decided to scrap the idea of using the volvo master cylinder and went to the auto parts store and got a sn95 cobra master cylinder. I cut the line going to the rear and got some brake line fittings for 3/16 m12x1.0 bubble flare and put the brake system back together. after that the brakes bled almost immediately and i had a nice hard pedal. Funny enough these are probably the best feeling 240 brakes ive ever had on a 240. I think the proportioning valves in the rear however have some garbage in them because the rear brakes seem to not be grabbing as hard as they should. for this i think my plan of attack is going to be to delete the rear proportioning valves and put a adjustable one up front. They are pretty cheap so i will probably get 2 just to have a backup. The whole goal of this brake system debacle was to delete some of the stuff that is becoming very hard to find and get a system that is simplified and ready for bigger brakes if i ever decide to swap to different wheels and tires.
Which Pelican brake lines are you referring to - are they front hoses for an early 911 like 
