After I complete a planned front-end rebuild (assuming winter finally ends), I need to flush the dirty, old brake fluid in my '77. What's the correct order for bleeding? Any other tips on the bleeding process? Thanks in advance!
Correct Order to Bleed Brakes on '77
- Thread starter kschlawin
- Start date
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RR, LR, RF, LF
HTH!
Sent from my iPhone using IH8MUD
HTH!
Sent from my iPhone using IH8MUD
Here's an awesome link on how to bleed them right for a 40 series so they are nice and tight. http://www.globalsoftware-inc.com/coolerman/fj40/15E.htm
Blue77FJ40
SILVER Star
LR, RR, RF, LF
The left rear is furthest from the master cylinder and has the longest run.
The left rear is furthest from the master cylinder and has the longest run.
Gotta disagree.
You should bleed the longest brake line first, the shortest last. So since the lines from the master go along the firewall to the right side, then go to the axles from there, that would be LR, RR, LF, RF. I would hope this matches the FSM, which I don't have right here.
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Blue77FJ40
SILVER Star
Dag, I've been doing the rears correct, but reversed the fronts. Hugely massive brain fart!
Properly schooled now, the next time I need to bleed, I'll have the correct order: LR, RR, LF, RF
I'm really glad I checked out this thread.
On the front, i guess I was looking at the MC, and thinking that the LF is closest to it, totally forgetting the run of the brakeline itself. DOH!
Properly schooled now, the next time I need to bleed, I'll have the correct order: LR, RR, LF, RF
I'm really glad I checked out this thread.
On the front, i guess I was looking at the MC, and thinking that the LF is closest to it, totally forgetting the run of the brakeline itself. DOH!
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- Thread starter
- #10
This is why I asked the pros! I was reading in various places, and seeing different answers. Thanks very much for the info!
It DOESN'T matter. Just remember the first on the axle bleed the most-you're going all the way . Next on the axle only needs to be done from the T out. It's already bled to the T which on especially the rears isn't much further.
DTSkyCop
SILVER Star
Great info here... I would do it the correct way too... lol
Why would it matter as long as you bleed both sides of the T? Does the bubble know which way is farther from the master? Please explain.
The general idea of starting the furthest distance from the master cylinder is to pull bubbles away from the other lines in the system first , then remove any residual air from the shorter lines . This prevents the longer lines from sucking air back into the shorter ones .
At least that's how it was explained to me around 35yrs ago...lol .
Sarge
At least that's how it was explained to me around 35yrs ago...lol .
Sarge
Really? How does bleeding the longer line pull a bubble out of a shorter line when there is no flow through the line that is not bleeding? If you can pull a bubble out of a shorter line by bleeding a longer one, then why can't you pull a bubble out of a longer line by bleeding a shorter one? Wouldn't this prevent the shorter lines from sucking air back into the longer ones in the same way? Please explain.
Venturi effect? Probably minor, but even a little could matter.
Totally agree. Whatever effect one line has on the other it can only make a difference within inches, at most, of the junction.
I guess that I see the logic in not worrying about the order, but I was taught "farthest first and work your way back".
Since you always do all four wheels following that rule doesn't complicate anything, so I'll keep it as a rule of thumb.
Since you always do all four wheels following that rule doesn't complicate anything, so I'll keep it as a rule of thumb.
I was taught the same thing: start with the farthest away.
Later in life my day job included questioning the veracity of things that people take for granted. Then I made the mistake of thinking about bleeding brakes and I couldn't figure out why it would matter, so I tried starting with the shortest line and ended up with the same good result.
Later in life my day job included questioning the veracity of things that people take for granted. Then I made the mistake of thinking about bleeding brakes and I couldn't figure out why it would matter, so I tried starting with the shortest line and ended up with the same good result.
I'm sure that has been the general "rule of thumb" since hydraulic brakes have been around. Probably helps a little if it's brand new at the factory and all completely dry/empty. I more or less do it that way too usually but haven't many, many times for many reasons-OR just done only ONE. Or maybe two. All different types and makes of vehicles- for years. Not so much in last ten years. Used to try different methods on difficult ones. Experimented too. I bleed the master by installing-leaving lines off-holding fingers over holes-having helper slowly pump-(fingers acting as check valves)-install lines-helper pump up-loosen line fitting to bleed then tighten-each one several times.
