1961 320 unit Need FI Help

[Willie R.]

Have a gas leak from the high pressure pump area along the drive shaft, have replaced seal & shaft, still leaking.Any help appreciated.

[Richard M.]

Re: 1961 320 unit Need FI Help

Willie,

Did you apply a tiny dab of Permatex around the perimeter of the seal? Since you have both pieces new, I'm wondering if the pump bore surface may have a slight defect and it's leaking around the perimeter of the bore and seal outside surface.

P4150027.jpg P4150038.jpg P4150035.jpg P4150040.jpg


Rich

[Willie R.]

Re: 1961 320 unit Need FI Help

Richard,Thank you for your response & pictures, used install instructions st 12 will take it apart again , the one thing that I did not due was clean out the bore with a wire brush.In installing the new shaft front to back a lot of resistance, should it go back to front?

[Mike M.]

Re: 1961 320 unit Need FI Help

when installing the seal in the pump housing, could u have rotated the seal 180 degrees? regards,mike

[Richard M.]

Re: 1961 320 unit Need FI Help

I seem to recall the same shaft install issue, so IIRC I went back to front, with some oil on the shaft & seal to ease it in.

Yes, I think you had a bit of dirt in there and is where it's leaking. I bet a cleanup and a tad of sealer and you'll be fine.

When the FI expert guys check in here they may have some ideas too. I'm just a rookie!

Rich

[Willie R.]

Re: 1961 320 unit Need FI Help

Went back and cleaned everything used sealer& installed shaft front to back, the pump turns with resistance is this normal. Want to correct this before installing??I really do not want any fuel leaks, this car is a driverActually first real problem with unit in 25 years.

[Richard M.]

Re: 1961 320 unit Need FI Help

Willie, was it substantially more resistance than before?

I have one here recently rebuilt. It has a slight drag and I measured it. It's only about 1 oz at the end of a 2.5" lever (Allen wrench ground down). When we rebuilt it we ran a drill while tightening the Allen cap screws holding the gear cover.

IIRC, John DeGregory told me the new shafts are slightly oversize to help mate with used bushings. New shaft along with a new seal is probably normal to have some drag.

Rich

[John D.]

Re: 1961 320 unit Need FI Help

Willie, After the bore is clean one needs to look inside the bore with a bright light to see if the fellow before you used a chiesel etc to remove the seal.
The new seals do offer resistance which can make it difficult to determine if you have the spacer installed correctly. You don't want the gears digging into the spacer. Also how do you know the guy before you installed it correctly in the first place. The spacer surrounds the two gears. Has to large holes in it.
The larger of the two holes is for the drive gear. The smaller of the two holes is for the idler gear. One needs to have giant pin gauges to determine the size.
Then you have the end plate that is held on with four allen head screws/bolts. This end plate needs to be lapped flat on a granite surface plate. Not a sheet of glass, not a counter top, and not anything but a machinist surface plate.
Here is one method to rebuild the pump. First assemle the pump with machining work, etc done. See how it turns and mark everything. SHould turn like a clock with no gear binding, no grinding noises.
Then last of all you take the pump apart and install the seal using the Permatex #3 Aviation. But you can get in trouble using this stuff. A little bit goes a long way. There is a high pressure hole on the inside bore of the pump. Make sure it's open and cleaned out. Make sure you do not plug it up with #3.
Just put a little bit of #3 on the very edge of the seal before you drive it in.
Hopefully you marked the depth of the old seal. If you did not refer to the ST12 manual and it will give you a dimension from the muchroom shaped too. (I think).
THose pumps are a pain to work on and today more are leaking than ever before. The ethanol is killing them. Make sure you bought a shaft and seal kit for ethanol. Not a cheap one with an old buna rubber seal. Good luck, John

Pump warning. Do NOT hurt the carbon bushings. Yes they are replaceable bya few knowledgeable people. But it's big bucks and takes forever.

[Richard M.]

Re: 1961 320 unit Need FI Help

Hi John,

Great information..... thanks for sharing your knowledge. As you know I'm new at this stuff and have been working along side Chuck McSheehy on a '61 unit. He's taught me much since I started working on this project.

We did exactly what you described to rebuild this HP pump here. We carefully noted location and the orientation of the gearset after marking them, removed the old seal using a tap to thread the ID and a large bolt to pry it out. We then cleaned the bore in inspected for any flaws. We used just a small dab of Permatex on the perimeter of the new viton seal to ensure a leakproof installation. We were sure to keep the high pressure hole clear as well.

Chuck had a special driver tool he had made many years ago to set the seal at the proper depth. We measured the before and after depth to be sure. When we reassembled the pump we lightly oiled the gears and gearset cavitiy and cover. Chuck's procedure was to loosely attach the cover Allen head screws. Then we attached a drill to the pump. As I was running the pump he began tightening the screws one at a time around the pump side to side to ensure a uniform fit. While running the drill he could feel the assembly to ensure a proper cover alignment and gearset "feel".

Below is a photo session I took when we did this work. The pump rebuild is deep into the photo session at Page 4 of the photo link.

http://s684.photobucket.com/user/richmz/library/Misc/FI Rebuild

Thanks to guys like Chuck, yourself, and many others I've had the pleasure to speak to and email with that have been helping me with this project, I now have confidence I never thought I would have regarding FI rebuild and restoration. I'm learning much from all of you FI experts.

Thanks,
Rich

[Willie R.]

Re: 1961 320 unit Need FI Help

does the seal set below the sight hole, can see seal approx. 1/4 viewI want to thank everyone for their responses Like I said earlier first time any real problem with this FI unit.

[Richard M.]

Re: 1961 320 unit Need FI Help

does the seal set below the sight hole, can see seal approx. 1/4 viewI want to thank everyone for their responses Like I said earlier first time any real problem with this FI unit.

Willie I'll get a few measurements for you shortly when I get back to the shop.......Rich

[Richard M.]

Re: 1961 320 unit Need FI Help

Willie, I get 1.085" from the top of the seal perimeter to the top of the housing, and 0.955" from the furthest hole edge to the top of the housing. That puts the seal 0.130" below the edge of the hole.

Note the tool we used drives the seal into the bore a fixed amount, i.e. 1.085".

Rich

[John D.]

Re: 1961 320 unit Need FI Help

Probably one of the worst problems I run into rebuilding the pumps is this. Pump seals that are epoxied in place. Removing that epoxy is a nightmare.
And then when you finally get the seal out you typically see a huge gouge in the cylinder wall. At this point you are in big trouble as Permatex #3 will not do the job.
Good luck if this happens. JD

[Richard M.]

Re: 1961 320 unit Need FI Help

Probably one of the worst problems I run into rebuilding the pumps is this. Pump seals that are epoxied in place. Removing that epoxy is a nightmare.
And then when you finally get the seal out you typically see a huge gouge in the cylinder wall. At this point you are in big trouble as Permatex #3 will not do the job.
Good luck if this happens. JD

John,
Sounds ugly. How do you get the epoxy out of it. Would a heat gun work?

Willie, Any luck yet?

Rich

[Willie R.]

Re: 1961 320 unit Need FI Help

Rich,Thanks for asking,replaced the seal no more fuel leaks, for now, no sign of any epoxy in the pump. New problem is that it will stay runningfeels like fuel starvation rebuilt fuel pump about 2 years ago, going to have it checked