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rjblunk
Bone Stock
Posts:5
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| 09/08/2008 12:01 PM |
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I need some advise. I have converted my 73 Fj40 over to all disc brakes using the kit for JT Outfitters. I now have my back brakes having continous pressure (it is like the pressure is not bleeding back). I changed my master cylinder to an 86 4 Runner but I still have the issue
Here is what I am thinking of doing -
1. adjust the foot piston rod (right now it is giving me no play but I am not sure why).
2. Proportioning valve for the rear discs.
Thoughts or suggestions?
Thanks
Rod |
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Dan Pitts
Body Lift
Posts:232
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| 09/08/2008 9:33 PM |
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| i would go ahead and just get a cheap manual poroptioning valve for the rear if i were you |
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Danny Pitts
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lift it, fat chicks can't jump |
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webby4x4
Forum Admin, Magazine Editor
Rock Star
Posts:2351
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| 09/08/2008 10:30 PM |
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I ran into the same problem when I converted my '74 FJ40 to all disc brakes (among other problems). I created a temporary solution by shortening the rod, but I was never satisfied with the stopping power (it sucked). Ultimately, I ended up changing out the master cylinder to an FJ80 unit. Here's the article that I did: http://www.4x4review.com/tech/fj80-MstrCylinder.asp
After I swapped this in, I didn't need a proportioning valve or anything - it just worked like a champ.
Rick |
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Rick Webster
Editor, 4X4REVIEW.COM - A Tork Media, Inc. Publication
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'74 FJ40 Land Cruiser
"Measure once, cut twice" |
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rjblunk
Bone Stock
Posts:5
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| 09/09/2008 6:55 AM |
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| Thanks guys. Nice job on the article. What year did I need to reference 90-95 when calling All Pro?
Rod
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webby4x4
Forum Admin, Magazine Editor
Rock Star
Posts:2351
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| 09/09/2008 8:57 AM |
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You're welcome, and thanks on the compliments. We didn't reference a year, we just told them what year FJ40 we had in the stable. They sent us the correct unit. Nice and easy... We've always been really happy with All Pro.
Rick |
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Rick Webster
Editor, 4X4REVIEW.COM - A Tork Media, Inc. Publication
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'74 FJ40 Land Cruiser
"Measure once, cut twice" |
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rjblunk
Bone Stock
Posts:5
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| 09/09/2008 11:47 AM |
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Update -
I read about the length of the brake petal and the booster petal also being a factor. I think (from testing below) that my booster piston was contacting the MC plunger when installed (already engaging). I think that my wheels were staying engaged and as I used the brakes in testing with the piston still engaging on from the booster to the MC plunger, the pressure would build up at the cylinders causing them to lock up after a could applications on the brakes and the pressure was not being released.
I took of my MC (with the lines attached and pulled out the booster piston. It has an adjustment on it so I adjusted it to the mimimal (up to the stop). Additionally for testing, I put screwed on nuts (for more spacing during this test) between the MC and the booster. I attached the MC back to the Booster and just took it for a test drive.
Results - The brakes no longer seem to be applied as before (I believe this is due to the MC plunger is now allowed to return to nuetral). This is good and addressed the continous lock up that I was experiencing.
Second - I now see the spongy effect that you mention regarding the brake petal and I think my back brakes are engaging first as mentioned regarding needing the FJ80 non ABS MC.
Here is what I think I will do -
1st issue -I plan to either cut down the piston or make a spacer. I think I will make a spacer (the nuts were about 1/4 spacing and I had a lot of throw to really engage the MC Plunger). So I am thinking of using 1/8 steel plate and making a spacer. I can fine tune with the booster piston since it has an adjustment capability. This should eliminate the constently engage issue.
Second - I am going to either get a porportional valve or the FJ80 MC. I checked on All Pro website and did not see any reference to the FJ80 MC there. I will call them. I saw from several others you can get a Marlin FJ80 non ABS MC from them for about $129. I think the FJ80 MC is the better choice since I will not have to cut the brake lines and reflare. Thougths on my Item 1? It was a little addition to the FJ80 MC issue. Thanks again.
One other thing. I am looking for a good off road club to join in the Annapolis, MD region. I grew up in Idaho where there were plenty of places but now I haven't been able to find any. Thanks. |
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rjblunk
Bone Stock
Posts:5
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| 09/09/2008 11:49 AM |
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| Danny - how hard was it to flare it. I see the flaring kits from $30 and the adjusting propotional valve at $80 so it is pretty close in cost. Thoughts and thanks.[?] |
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Dan Pitts
Body Lift
Posts:232
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| 09/09/2008 10:55 PM |
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| its not bad at all the last one i installed was aon a race car and it took just a matter of minutes to install it and then the rest of the time was spent on bleeding the brakes. thats the route i would go you can even rent the flaring tool from autozone for free. |
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Danny Pitts
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lift it, fat chicks can't jump |
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