ConcoursMustang Forums
1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year => 1970 Mustang => Topic started by: Kdclem on July 26, 2024, 03:10:38 PM
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Attempting to rebuild a Disc Brake Proportioning Valve DOOA 2B328 D, 1970 MAch 1. The short piston was removed no problem. The longer piston is a devil to remove. Needle nose won't go in a capture it, even ground the tips so they would go in farther. Soaked the unit in brake fluid for 3 days and still no. Decided to try and plug off some ports and use compressed air 150 psi., and now the small brass piece inside the port decided to come loose and fly out - lost. Does anyone know how to get the longer piston out? and is the missing piece in the middle port available? Is it soldered or does it press in when the fitting becomes tight? Thanks in advance.
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Attempting to rebuild a Disc Brake Proportioning Valve DOOA 2B328 D, 1970 MAch 1. The short piston was removed no problem. The longer piston is a devil to remove. Needle nose won't go in a capture it, even ground the tips so they would go in farther. Soaked the unit in brake fluid for 3 days and still no. Decided to try and plug off some ports and use compressed air 150 psi., and now the small brass piece inside the port decided to come loose and fly out - lost. Does anyone know how to get the longer piston out? and is the missing piece in the middle port available? Is it soldered or does it press in when the fitting becomes tight? Thanks in advance.
That is the distribution block and not the proportioning valve . The proportioning valve is a different piggyback part. I am not aware of distribution block parts being sold seperate. If air does not get the piston out then you can drill a small hole on the opposite side and use the hole to take a rod to push or hammer the piston free. After you get piston out you thread the opening and use a appropriate sized allen screw and thread it in so to seal the hole flush with surface.
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Thank you for your reply Bob. I was hoping for a better solution, but unless there's a special tool out there that can grab hold of it while still in the hole, might not have another choice. added some more photos. Anyone else had a similar problem?
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Two methods that have worked for me and others come to mind, and have been discussed previously, but on pre-1970 models which is why it might not have shown up on your search results...assuming you searched for an answer of course.
1. Pick a port, any port, behind the shuttle valve. Use fittings to adapt a grease gun. Cap off the other port. Then use hydraulic pressure to move the valve out.
2. The less finesse, more he-man approach is to heat it up (propane fine, don't need anything more than that), grab it with a sufficient glove (this is pretty important if you don't want a distribution block 1:1 scaled tattoo in your palm), and bang it down hard on a hunk of wood (so as to not dent the brass block).
I have Kevlar gloves that are perfect for this, and never spent the time getting the fittings set up for a grease gun, so you can guess which way I use.
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Hopefully you will get the piston loose and or find your missing parts. When it comes time to bleed the brakes many vendors (NPD comes to mind) sell a tool that threads into the brake switch hole that is made with a fixed metal pin that keeps the piston centered while you are bleeding the brakes.
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Two methods that have worked for me and others come to mind, and have been discussed previously, but on pre-1970 models which is why it might not have shown up on your search results...assuming you searched for an answer of course.
1. Pick a port, any port, behind the shuttle valve. Use fittings to adapt a grease gun. Cap off the other port. Then use hydraulic pressure to move the valve out.
2. The less finesse, more he-man approach is to heat it up (propane fine, don't need anything more than that), grab it with a sufficient glove (this is pretty important if you don't want a distribution block 1:1 scaled tattoo in your palm), and bang it down hard on a hunk of wood (so as to not dent the brass block).
I have Kevlar gloves that are perfect for this, and never spent the time getting the fittings set up for a grease gun, so you can guess which way I use.
I use the heat and bang method. It has never failed me.
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Grease method.
https://www.musclecarresearch.com/grease-gun-pressure
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Hopefully you will get the piston loose and or find your missing parts. When it comes time to bleed the brakes many vendors (NPD comes to mind) sell a tool that threads into the brake switch hole that is made with a fixed metal pin that keeps the piston centered while you are bleeding the brakes.
https://www.musclecarresearch.com/brake-valve-tool
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Follow Up - was able to use high pressure air and it shot across the shop like a projectile. Thanks everyone.