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Old 11-05-2022, 03:00 PM   #1
bkaushansky
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Default Brakes - sanity check…

‘88 245 with RX7 front calipers and stock rears. OEM master cylinder.

My brand new Volvo OEM brake junction block crapped out and is leaking at the switch. Don’t need the switch so I was planning on using a M12x1.0 plug and copper washer. BUT… if fluid is leaking past the internal o-rings (slowly) should I be concerned?

I’m thinking, no since assuming I remove all air bubbles the pressures will equalize. I would still maintain 2 separate circuits just in case.

Then there’s the other option of pulling the internals of the junction block completely out. This creates a single circuit utilizing the stock rear proportioning valves to create pressure differential (front to rear). This would eliminate any possibility of a fail safe.

Thoughts?

B.
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Old 11-05-2022, 03:05 PM   #2
Radtap
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Fluid should not pass between the two halves of the junction block, you can easily remove the center pin and other parts to replace the o rings inside of the junction block.
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Old 11-05-2022, 04:00 PM   #3
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I just bought the correct sized ball hone from ebay and the o-rings from Volvo to rebuild an original Volvo junction block.

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Fluid should not pass between the two halves of the junction block, you can easily remove the center pin and other parts to replace the o rings inside of the junction block.
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Old 11-05-2022, 04:15 PM   #4
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If the fluid is leaking past the o-rings then it can also potentially leak between the circuits. In the UK at least 1990+ models came with a junction block that had no switch (instead relying on a mc level sensor). That would be a better option.
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Old 11-05-2022, 07:02 PM   #5
dl242gt
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If you don't want to rebuild the warning light valve. I would contact plantman or hiperfauto and see if they have any of their junction block eliminators left.
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1982 242 turbo. 338k miles. MVP coilovers and 3" exhaust. Flowed 405 with a V15. Cossie turbine housing with upgraded compressor housing. 90+, IPD remote oil filter. Some other goodness, too. Been lots of fun over 25 years. Restored in 2k. Now ready for a 2nd restoration.

1993 245 Classic, 440k miles, enem V15. IPD bars and chassis braces. Simons sport exhaust from Scandix. sbabbs ezk chip. Been a good road warrior. Genuine Volvo rebuilt leaky M47.
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Old 11-06-2022, 05:48 PM   #6
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Quote:
Originally Posted by dl242gt View Post
If you don't want to rebuild the warning light valve. I would contact plantman or hiperfauto and see if they have any of their junction block eliminators left.
Unfortunately, the supply of new junction blocks without a warning switch has been exhausted.

So I'm looking into rebuilding the original junctions with warning switches and that's why I bought the o-rings from Volvo and a suitable sized ball hone to clean up the passage a couple.
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Old 11-06-2022, 06:02 PM   #7
dl242gt
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Well, it's better if it's safety first. I would rather have the warning light.
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Old 11-06-2022, 06:31 PM   #8
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Quote:
Originally Posted by crogthomas View Post
If the fluid is leaking past the o-rings then it can also potentially leak between the circuits. In the UK at least 1990+ models came with a junction block that had no switch (instead relying on a mc level sensor). That would be a better option.
1991 in the US, then in 92 they went to ABS and eliminated the junction
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Old 11-07-2022, 12:13 PM   #9
bkaushansky
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Got a solution!!

For those with single line front caliper upgrades, I replaced the junction box completely with 2 Tee fitting. This maintained 2 independent circuits. The fluid sensor is now in the cap and it just so happens the wiring is plenty long enough to reach, almost as if intended to go there. The Tee fitting I used were Empi 10mmx1.0 bubble flair for a VW Bug. Made a “U” bracket out of steel to hold the tee fitting in same location.

B.
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