100% new brake system 0% pedal

sloanstavern

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For sale- ‘82 FJ 45. Looks good…..runs ok…..won’t stop….. no reasonable offer refused.

It’s almost to that point, confirm the back brakes were OK bye isolating that circuit the wheels would spend but I had instant pedal within a half inch or less and it held pressure great.

Went through both sides on the front making sure they were adjusted properly and no other issues, conducted a thorough gravity bleed . Both bleeders fully opened slowly pressing down and then slowly releasing. I saw no bubbles in the reservoir and on the down stroke the fluid level did not move and on the upstroke it just slowly dropped down.

I don’t think this is a push rod issue since the back brakes function perfectly.

One note, I did isolate one front wheel and then the other, each time the pedal got more firm by a similar amount so whatever the issue is I seem to have it equally in both front wheels
 
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OK, ?, you have correct MC now as determined by those who know, everything tests normal except front brakes ? You stated in your original post that you replaced all brake components, There are different dia./volume wheel cylinders, is it possible that your MC is designed to work with smaller wheel cyl.'s ?? That would be a possible explanation, that the Master Cyl stroke just aint enough to fill the front wheel cyl., just a thought.
 
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@peesalot is onto something. Previously Kurt had determined that your PO had installed an incorrect MC for a front drum braked 45. He also mentioned that your front wheel cylinders may also be incorrect since the 45s have larger front drums. I recommend looking back at Kurt's post and confirming that you have the correct front wheel cylinders.
 

sloanstavern

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OK, ?, you have correct MC now as determined by those who know, everything tests normal except front brakes ? You stated in your original post that you replaced all brake components, There are different dia./volume wheel cylinders, is it possible that your MC is designed to work with smaller wheel cyl.'s ?? That would be a possible explanation, that the Master Cyl stroke just aint enough to fill the front wheel cyl., just a thought.
Thanks for the tip. Here is what came out.

the replacement wheel cylinders are generics for an older 40 with front drums ( I ordered them 2 years ago before I realized how non standard a non usa sled is)
BF837F6B-DD73-4D6D-994A-50655BE04781.jpeg
85D5E45C-3E10-4B85-8044-CBE4B2DD1911.jpeg
 
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Thanks for the tip. Here is what came out.

the replacement wheel cylinders are generics for an older 40 with front drums ( I ordered them 2 years ago before I realized how non standard a non usa sled is)
View attachment 2956997View attachment 2956998


What you have is probably standard for markets that still had drum brakes on the front axle 8/80+ You rear axle should only have brake cylinder on each side.
 

Skreddy

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For sale- ‘82 FJ 45. Looks good…..runs ok…..won’t stop….. no reasonable offer refused.

It’s almost to that point, confirm the back brakes were OK bye isolating that circuit the wheels would spend but I had instant pedal within a half inch or less and it held pressure great.

Went through both sides on the front making sure they were adjusted properly and no other issues, conducted a thorough gravity bleed . Both bleeders fully opened slowly pressing down and then slowly releasing. I saw no bubbles in the reservoir and on the down stroke the fluid level did not move and on the upstroke it just slowly dropped down.

I don’t think this is a push rod issue since the back brakes function perfectly.

One note, I did isolate one front wheel and then the other, each time the pedal got more firm by a similar amount so whatever the issue is I seem to have it equally in both front wheels
I would not rule out pushrod. If your depth is too deep, it’s already pushing the piston part of the way through its stroke at rest because it won’t fully retract. This means you aren’t getting full fluid volume. If the pushrod is not deep enough, a portion of your pedal travel is doing nothing but taking up the slack, so you’ll never get full volume.

Another thing to verify: Are your lines hooked up to the proper port on the master cylinder?
 

pb4ugo

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Did you ever figure out what that does?

I just tore m/c apart last week. I think it keeps the front piston in place. There is a spring in front of each piston.
The frt piston had a heavier spring. The bolt keeps the forward piston from moving to far towards the back piston.
20220319_201611.jpg
 

Pighead

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I just tore m/c apart last week. I think it keeps the front piston in place. There is a spring in front of each piston.
The frt piston had a heavier spring. The bolt keeps the forward piston from moving to far towards the back piston.
View attachment 2957287
I thought it did something like that. Wondering if it could be interfering with the front piston if not installed correctly...
 

sloanstavern

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I would not rule out pushrod. If your depth is too deep, it’s already pushing the piston part of the way through its stroke at rest because it won’t fully retract. This means you aren’t getting full fluid volume. If the pushrod is not deep enough, a portion of your pedal travel is doing nothing but taking up the slack, so you’ll never get full volume.

Another thing to verify: Are your lines hooked up to the proper port on the master cylinder?
Curious- the fittings at the MC appear to only fit one way, However across the engine bay and down on the frame rail where it joins a T fitting, I wonder if those can be crossed? On the MC which fitting is for the front and which is for the rear?

7677B034-DBDE-4E39-A17F-4248D7BFB122.jpeg
 

pb4ugo

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The frt reservoir is usually for the frt brakes on US spec. drum or disc.
 

sloanstavern

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The frt reservoir is usually for the frt brakes on US spec. drum or disc.
Thanks Mine is non USA and a single reservoir
 

pb4ugo

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It's single reservoir but it has a hose feeding where the other reservoir would be. You have 2 lines coming out of it 1 for the frt and 1 for the rear. A true single res would only have 1 line coming out of it.
 

sloanstavern

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It's single reservoir but it has a hose feeding where the other reservoir would be. You have 2 lines coming out of it 1 for the frt and 1 for the rear. A true single res would only have 1 line coming out of it.
Got it my question is - Does the front most port on the MC feed the Front or rear brakes? There is an outside chance at the frame rail the lines are crossed.

I have it plumbed the way it came to me but that's not saying its correct...
 

pb4ugo

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Follow the lines. The line towards the frt at the master is probably for the frt brakes.
 
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...
 
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How about for s***s and giggles you take pictures of absolutely everything from the master, to lines- following them their entire path on all feeds and another set of pics of all 4 corners with drums off exposing drums shoes and wheel cylinders, maybe someone will see something amiss...we're grabbing at straws here it can't possibly hurt.
 
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sloanstavern

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How about for s***s and giggles you take pictures of absolutely everything from the master, to lines- following them their entire path on all feeds and another set of pics of all 4 corners with drums off exposing drums and wheel cylinders, maybe someone will see something amiss...we're grabbing at straws here it can't possibly hurt.
Thanks that is next on the list, I think PAL is onto to something with the incorrect wheel cylinders up front. I'm doing some digging this AM
 

sloanstavern

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Why is it the most painful wounds are self inflicted?

As far as I can tell I ordered and installed all the incorrect wheel cylinders ( again this was before I realized what a special and Unique girl I was dating). The OEM numbers do not match up, and it appears the correct OEM numbers might be a Unubtanium.
 

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