Roosa master rebuild question

JPayne · Jan 13, 2019

I am attempting my first rebuild on a JDB roosa Master pump. The hydraulic head is my issue. I took out three screws located on the top. According to picture. As I was disassembling the head I suddenly saw a short and long pin. Does anyone know where they go?
Thank you

Dieseltech · Jan 13, 2019

The short one is the vent wire, it goes in first in the ANGLED hole, and the longer retainer wire goes on top, then the plug. WHY did you remove the leaf spring?? That should have been left alone unless you have the centrality gauge to set the rollers correctly..

jm. · Jan 13, 2019

Just not work for a novice, hope you the best of luck but most times when I have seen this tried it ended up going to a pump shop.

JPayne · Jan 13, 2019

First and foremost Thank you
The manual did not show that part of it
I looked for hours on line with no luck
And I do have a gauge to set the rollers

Thanks again

JPayne · Jan 13, 2019

Thanks Jim will need as much luck as I can get
I have rebuilt motors transmissions axles carburetors
Just about everything but an injection pump
But I figure I wont learn if I dont try
Worse case I fork over the money to have it done

JD Seller · Jan 13, 2019

Yes removing that leaf spring just made it to where you have zero idea of the fuel setting now. That spring limits how far out the rollers come and that in turn controls the pistons under the rollers. This set the maximum fuel delivery the pump can deliver. It is a very sensitive adjustment. A half a turn on the screw that holds the spring on can easily be 1015% different is the top fuel delivery.

So a word of caution to any others out there that are "rebuilding" one of these pumps because of a governor ring failure. You do not have to take the entire pump apart down to this level. You can slide the roller/guides out and then the plungers with the leaf spring in place. You just need to clean out the fuel passages in the head. 95% of the time compressed air with do this fine. I am not a professional pump guy but have done 40-50 of these that just have that ring fail.

JPayne you will need to have the pump ran on a test stand to have the fuel metering set.

JPayne · Jan 14, 2019

i have another question Just trying to get through this
On a JDB435MB3795
What is the roller to roller spec tollerence

Roosa master rebuild question

JPayne

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Dieseltech

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jm.

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JPayne

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JPayne

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JD Seller

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JPayne

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