I'm pretty sure you have 4 flex lines... one from frame to rear axle, one from frame to front axle and one to both front calipers...
Replacing All Brake Lines - A Ton of Questions
- Thread starter RWBeringer4x4
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I'm pretty sure you have 4 flex lines... one from frame to rear axle, one from frame to front axle and one to both front calipers...
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- #42
you want the front to lock up first - if whatever set-up you have accomplishes that without a proportioning valve, more power to you (pun intended)
I ran front disks/rear drums on the 40 for a year without the valve just fine - the disks from the Man-a-Fre Wilwood kit are really strong
but when the GM-type rear conversion went on, the rear would lock up before the front without the PV, so on came the proportioning valve
I haven't seen this as hotly debated here on the forum as some seem to think
Well, it's no real debate for me. $40 and change for a valve is drop in the bucket compared to the rest of the overhaul, so I'd might as well plumb it in.
Thanks! Lots of good information there. I was thinking of ordering my flare nuts and tubing from FedHill. I think I counted 26 flare nuts on SOR's brake line picture, so I'm ordering two 12-packs. I think I'll be doing away with some by getting rid of the hard lines at the drums/calipers.
I think I will wind up with 6, for a full disc conversion. I'll have two to the front calipers, two to the rear calipers, and then the firewall to front axle drop line, and a frame to rear axle drop line. Haven't been under the truck recently, so can't confirm yet.
Weight transfer sounds like* a good argument for why the rear discs to lock, but I think it has to do more with the hydrolics.* When I did this conversion without a P/V & applied the brakes I coud feel the rear squat plus the rears would lock at slow speeds too.* Plus when on the trail the rears were more sensitive.* I think a lot of this effect has to do w/the frt calipers having 4 pistons w/ certain diameters & the rear M/C calipers having 1 piston w/a certain diameter.** I thought the adjustablity of the P/V would be cool, but when I found that happy spot I have never changed it.** I made my own tombstones. they're relatively easy to make.* When I see pics of folks doing the rear discs, I don't understand why they run their bakelines on top of the U bolts & axle, where the bumpstops can hit them. I know it looks good & is easier, & with a spring lift that contact may be a remote possibilty, but to me, it's just wrong.**
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- #44
Do you run yours under the spring? Doesn't that increase the likelihood of it getting taken out by a rock or a branch or something
I had the same question when I was doing my rear discs...
https://forum.ih8mud.com/hardcore-corner/460486-rdb-line-routing.html
https://forum.ih8mud.com/hardcore-corner/460486-rdb-line-routing.html
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- #46
Only difference is I'm staying SUA - so if I run it under the spring pack, there's no axle between me and debris. I guess based on that same concept, I could run it along the back of the axle, above the spring, and probably be fine... The axle would need to bottom out before the line got crushed...
Yeah, guess I mis-counted soft lines, forgot to count the two I had at each rear caliper. I didn't use a soft line running from the firewall to the front axle. Hardline to the tombstone clips (this line is ridgid) and soft lines out to the calipers.
Where are you going to weld in the tombstone clips?
Where are you going to weld in the tombstone clips?
Rick your right, If you run the brake lines under the spring they will get crushed. I thought I posted a pic of how I ran the lines on the rear of a 75 FJ40. It's the way I decided to run them, there are certainly many other ways to run them. I try to run them in a way they are protected from the trail & the vehicle.
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There are two cylinders at every wheel. But the fronts have 2 pistons per cylinder whereas the rears have a piston at one end and a static adjuster at the other. Hence 4 pistons per wheel at front and 2 pistons per wheel at rear.
Not gonna help you. Brake fluid is a dessicant and brake lines rust from the inside - contaminating your brake fluid and pads/shoes, and ruining your stopping power long before the lines are visibly damage or fail completely. This is why you should either use copper lines or replace your steel ones every few years. Not to mention you should change your brake fluid regularly and make sure your reservoir has its lid on.
I have heard of using stainless steel lines so this might be a solution but not sure of the pros and cons apart from corrosion resistance and high cost.
my lines of course are copper alloy manufactured specifically for brake lines. Can you even buy copper brake lines that are just plain copper?
he is from spain and other countries do stuff differently. here in the states, it's two pistons per rear cylinder and one piston per front cylinder.
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- #54
I don't know yet - I'm still debating exactly how I will run the caliper lines. I really like pb4ugo's setup, but he is running a U-bolt flip kit, that I will not have. I'll need to mount mine differently.
You did, thanks! Sorry, I must have missed it, or it didn't show up on my phone. Your method is elegant, but you have flipped U-bolts in the rear - so I'll need to come up with something different.
That's what I'm going with. I don't think you can buy DOT approved pure copper line for brakes because of the high-vibration (fracture prone) nature of the application.
having removed, reconditioned, and reinstalled tens of these 40 series wheel cylinders, I can absolutely, definitely confirm that I got that the wrong way round.
As in the attached foto, the rear (on the left) is open at both ends for two pistons. The front is blocked between the piston end and the static adjuster end.
Thinking about this more, in my 40´s the MC is two part - its a single cylinder but with two pistons and two springs of different sizes and two brake lines coming out of the cylinder. So the pressure in the rear system is going to be different to the pressure in the front system. But in the 45´s the MC has one piston and one brake line exiting it that then splits into front and rear at what looks like a T piece. Will have to take a closer look tomo. Maybe this is a proportioning valve? All my Toyotas only have drums.
Off subject but when I do my rear brake line i was going to do my gas line at the same time. Can I use 3/16 nickel copper for my fuel line? Is it big enough? Will the copper alloy work with gasoline?
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- #57
From my reading, it is safe to use with gasoline (no personal experience in that boat, yet). That said, I have no idea if 3/16" is going to be sufficient. I believe fuel line is usually closer to 3/8".
- Thread starter
- #58
Ok, well, here goes nothing:
I started to practice bending brakes last night - and, while getting the ANGLE is easy, getting the angle in the right spot is tougher. So, a few more questions:
1. Is there a good "quick and easy" way to get the proper bend LOCATION in the line - without a refresher course in geometry/pre-calc.
2. Still curious to know if I will need a spacer between an FJ60 master cylinder, and the booster (or trim the booster rod) to make everything work...
3. Is it easier to pull the lines out of the truck, and use them as templates, or bring the new line TO the truck, and try to bend them on-site?
That said, I'm currently running a non-stock booster, with the stock MC so it is possible it has already been modified - I guess I will find out!
I started to practice bending brakes last night - and, while getting the ANGLE is easy, getting the angle in the right spot is tougher. So, a few more questions:
1. Is there a good "quick and easy" way to get the proper bend LOCATION in the line - without a refresher course in geometry/pre-calc.
2. Still curious to know if I will need a spacer between an FJ60 master cylinder, and the booster (or trim the booster rod) to make everything work...
3. Is it easier to pull the lines out of the truck, and use them as templates, or bring the new line TO the truck, and try to bend them on-site?
That said, I'm currently running a non-stock booster, with the stock MC so it is possible it has already been modified - I guess I will find out!
Pull the lines from the truck and use it as a template. As far as the right spot, just practice...
Straight wire , especially the 3' lengths of TIG wire are great for bending up exact templates of brake lines - you can buy it by the pound at any welding supply worth their salt . Be wary of those tightly bent ends , unless it's the newer nickle-copper alloy those are a tough bugger .
Sarge
Sarge