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  1. #1
    Expert Bosshoss's Avatar
    Join Date
    Dec 2009

    Dillon 550 press rebuild

    I posted this on another forum and thought I would share here.

    Dillon 550 rebuild.

    I just finished PMing one of my 550's and thought I would do a write up of what is involved.
    I wish I still had a 650 and Square Deal so I could do a write up on them.

    First thing you will want is a alignment tool from Dilllon. Call them and they will send you one NO CHARGE.
    You can do it without the tool but it is easier with it.
    Alignment tool

    You will need a empty tool head and a powder drop die if you are using the alignment tool.

    First thing is strip the press. Remove toolhead with dies and powder measure.
    Remove priming system.
    Remove shell plate and brass station pins.

    IMPORTIANT next find and remove the 2 bolts(picture below) from plate setting on top of the ram.(under the shell plate that you have already removed) These bolts need to be removed first as they will be hard to loosen if you undo the linkages first. The plate on top of the ram must be removed first or ram will not come up thru the opening on the top of the press(where toolhead goes).

    Picture of top of ram with plate removed.

    Set this plate aside and be careful not to lose the detent ball and spring that sets in this plate.

    Note the position of the 2 linkage arms. Left arm should have Dillon cast into it on the left hand side. Right arm has the knob that the primer catch bin sits on.

    Older presses have a circlip holding in the pin that connects the 2 linkage arms.
    Newer presses have a nut with a grease zerk. While this is a nice feature the rest of the linkages still need some grease.
    Remove RIGHT circlip or nut which ever you have. RIGHT side ONLY.
    Note the washers in between the arms and rocker. Old style has wave washers.
    Push the pin from right to left Catching the washers as the pin passes thru them. (might need to use a punch and small hammer if the press has been used a lot). [Note: See post #18 if your press has the newer nuts rather than circlip. The bearing is stepped and cannot be driven out.]

    Next is the pin on the bottom of the ram. CAREFULL there is a set screw that comes up from the BOTTOM of the ram. Raise the ram and loosen the set screw until pin comes out. Pin has a groove in it that the set screw fits into. You don’t need to completely remove the set screw. Just loosen enough to remove pin.
    Rocker(with operating handle) is loose now and can be set aside.

    Picture of bottom of ram and set screw.

    Picture of pin with set screw groove.

    Ram is now free to remove. Push up from bottom and grab the top part and pull straight up and out of press.

    Last thing is the linkage arms. If you look these are hanging on pins that are splined into the press.
    One of the pins has a hole in it.
    I use a brass squib rod to put thru the pin with the hole in it. The other pin is a solid pin. Drive out the solid pin with the rod thru the hollow pin.

    Solid pin coming out.

    Now take the rod and put thru the hole where the solid pin(that you just drove out) was and carefully put it on the back EDGE of the hollow pin. Now drive out the hollow pin.

    Hollow pin coming out.

    Linkage arms should be free.

    Clean everything up and check linkage arms for galling. Clean up any galling.
    Clean up the hole in the press body that the ram fits into.

    I use wheel bearing grease on all the pins. But any good automotive grease will work.
    I use a thick oil on the ram(30 weight).
    Reassemble in reverse of how you took apart.
    Linkage arms first (make sure the one with the knob for the spent primer catch is on the right and right side up). Left linkage arm should say Dillon on left side and right arm should say on right side.
    Pins will slip all the way in until splines hit press. Tap them in until flush.
    Put ram back in the press.(note set screw that holds the shell plate bolt goes to the left side)
    While you have the rocker assembly off if you have a roller handle now is a good time to put a drop of oil in the end of it.
    Rocker assembly next. Put the greased pin(the one with the groove in it) thru the rocker assembly and ram. Tighten the set screw on the bottom of the ram. Make sure the set screw is in the groove. (pin should be almost flush on both sides).

    The long pin is next. It fits thru the linkage arms and rocker assembly. One end of this pin should have the circlip or nut still on it. Grease everything up and slip the pin thru the left linkage arm first. DON’T forget a washer fits between each linkage arm and the rocker assembly. Feed it thru left linkage arm- washer- rocker assembly- washer- right linkage arm. Put nut or circlip on the right side.

    Put the plate back on top of the ram. Don’t forget the bracket for the positive powder return. It goes under this plate.
    Just lightly tighten the 2 screws that holds the plate on the ram.

    Put empty tool head in press and use the pins that hold it in.
    Install powder thru die in station #1 (Size and prime position) screw it in about half way.
    Put the alignment tool in the powder drop die.

    Raise the ram and the tool should slip right in the hole in the plate that the primer comes thru.
    If it doesn’t loosen the 2 screws slightly and move plate around until the tool slips into the hole without hitting plate.
    Tighten the 2 screws and check again that when the ram raises that the alignment tool goes into the hole in the plate with out touching the plate.

    Clean up primer system and powder measure and finish reassembling everything.

    Mine had 10K rounds loaded on it since last teardown and it was fine grease wise. Just needed a general cleaning around primer system and shell plate.
    I probably won’t disassemble again until 25K unless I feel like it is starting to drag.
    My press is kept in the heated and air-conditioned house. If kept in a unheated building or garage the press might need serviced more often.
    Last edited by lovemywoods; 02-16-2016 at 16:37. Reason: Added directions to modified step.

  2. #2
    Meekness ≠ Weakness
    Que's Avatar
    Join Date
    Feb 2009
    I can barely convert my press between the various calibers, so I know I can't do this.
    Rudeness is the weakest person's demonstration of strength.

  3. #3
    Grandmaster rvb's Avatar
    Join Date
    Jan 2009
    IN (a refugee from MD)
    Quote Originally Posted by Bosshoss View Post
    Mine had 10K rounds loaded on it since last teardown and it was fine grease wise. Just needed a general cleaning around primer system and shell plate.
    I probably won’t disassemble again until 25K unless I feel like it is starting to drag.
    very nice write-up. hopefully those pics are on a server where they won't disappear in a couple months.

    Mine has approaching 150k, and I've never had it down THAT far. I've never removed the two link arms. I've only torn it down once that I recall. I didn't use a tool to put the plate back on top the ram, just went by the primer bar's alignment to the plate from underneath... maybe I just got lucky? I guess I'd rather be lucky than good, it's still working really well for me....

    I do keep the main ram lubed as well as squirt lube in the holes on the arms from time to time.

    but seriously dude, that's about as often as I detail clean my guns!!

    Ryan V. B. TY56060 Come shoot USPSA w Ft Wayne Area Practical Shooters:

  4. #4
    Expert bmbutch's Avatar
    Join Date
    Aug 2010
    Southern Indiana
    Incredible write up, thank you for taking time to detail that process out!
    What chains can hold belongs to man, the rest belongs to God! - Joshua Gianavel

  5. #5
    Master Slawburger's Avatar
    Join Date
    Mar 2012
    Almost Southern IN
    Possible sticky to preserve the pics?

    Very good post.

  6. #6
    Expert Bosshoss's Avatar
    Join Date
    Dec 2009
    Ryan you are right the press doesn't need to go down that far very often. I did it this time because a friend on another forum asked for it.
    It only took me a hour and a half and 20-30 minutes of that was wiping my hands. Everytime I touched something had to wipe hands off trying to keep grease off the phone/camera.
    It took almost as long to type it up and load pictures.

    I have only used the alignment tool one time and it can be done without the tool, just a little more fiddling around.

    150K I would say it is time
    Last edited by Bosshoss; 01-16-2015 at 20:41.

  7. #7
    Marksman PappyD's Avatar
    Join Date
    Feb 2008
    Indy northside
    This is great information and a big thanks for taking the time and effort to document the whole process.

    I took mine apart a few years ago but did not use the alignment tool. Didn't think anything was wrong.

    My question- How can you tell if the alignment is off enough to warrant the teardown? I pretty much just did a "spring cleaning" with new lube/grease etc. I keep it clean around the press. Use an old shaving brush to brush away powder, etc. I probably have 7-8K loaded since that cleaning. Everything seems to run ok- primers line up easy and so on.

    Maybe I can't tell ??

    Thanks again-


  8. #8
    Expert Bosshoss's Avatar
    Join Date
    Dec 2009
    Tear down was to lubricate pins and linkages.
    Alignment was OK before teardown.
    When the pins get dry the press gets harder to cycle. This happens gradually and that makes it hard to notice kinda like the shocks on a car. You don't notice the shocks are bad until you replace them.

    I have seen and bought a couple of used presses that had set for a few years and the grease had dried out on them. They needed tore down and re lubed.
    If some one is only loading 2000-3000 rounds a year the press may never need to come apart if you can get some oil in the holes in the linkage arms.

    You can send the press back to Dillon and they will rebuild it for like $75 plus shipping to them. Probably around $100 total.
    I would rather have 3500 primers and do it myself.

    BTW a 650 and Square Deal are not to bad to rebuild. IIRC my SD was mounted to the bench and not on a strong mount(I don't think they had a strong mount for the SD back then) and it had to be removed from the bench to rebuild it, which was a extra step.

  9. #9
    Expert dsol's Avatar
    Join Date
    May 2009
    Nice write up! I just sent my Square Deal off to Dillon last week for a rebuild. I had been experiencing trouble with the primer feed, sticking and snapping the ram so they would pop up sideways or upside down if I moved too quickly. I contacted them to get some advice, tried to adjust it per their instructions with little improvement so they told me to send it in. I love their lifetime no BS warranty, that was one of the two reasons I bought a Dillon in the first place.

    Someday I will find me an old 450 for lower volume miscellaneous loads or load development that I do not want to go through the setup on the SDB. I can use all my regular dies in it, right now I use a single stage press for load development, but it would be nice to have something else to add to the bench.
    Nature eliminates the stupid, regrettably the stupid breed faster.

  10. #10
    LoaderHolic billybob44's Avatar
    Join Date
    Sep 2010
    In the Man Cave

    Thumbs up You CAN do this Que...

    Quote Originally Posted by Que View Post
    I can barely convert my press between the various calibers, so I know I can't do this.
    Que, we have all the faith in the world that you can do this!!

    Make sure that you, and LoveMyWoods,(another 550 owner) gets this into a sticky..Just in case I have to do this to MINE down the road..HA HA..

    Thanks in advance...Bill.

    PS: Sorry I forgot--Thanks SO much for the Thread..
    "It's more important to have a gun in your hand than a cop on the phone".

    NRA Life Member since 1976+Outdoor Sportsman

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