How do I get the Detent Plungers Out?

[Lakeland997]

I've been busy stripping a couple of remote gearboxes ready for bead blasting and rebuild but the detent plungers in both have so far defeated me. Any tips?

[rich@minispares.com]

put the case in boiling hot water and let it soak for a while to expand the case

then look at the little holes drilled in the case across where the detent spring go, with a tiny screw driver you can poke the detent springs along a bit at a time, this will get the springs and the first detents out.

for the back detents you can poke them out with a bit of stiff wire - I use a selection of allen keys, as they are tough enough to wriggle around and are often just the right length to be able to hook around the various drilled holes

some times it helps to spray WD40 down and work them back and forth, it can take ages to get them out.

oh, and bead blasting remote cases is a nightmare, as all the beads get into the detent holes and block them all up again........ you need to clean them with vapour or something that doesn't leave stuff behind.

ive seen boxes beadblasted, then built and the detents bind up and jam solid, the only way to sort it is to strip the box and start again.

[ricardo]

Rich said it all, but just to add that compressed air is useful for the reverse plunger which is the harder to take out. Having the hole as clean as possible is essencial and a thick wire which fits the small hole on the side and can be bent as needed, helps too... to push the plunger. It can be done, good luck.

[ivor badger]

Do you really want the selector shafts, bearings etc out the box if shot blasting it? I would seal up these with old bearings and shafts to avoid any damage to the machined surfaces.

[CooperTune]

While not the the answer to your question I do a lot of trannys. I keep a plastic butter tub with a set of bolts. After stripping and degreaseing a tranny case I chase all threaded holes and install these bolts finger tight before bead blasting. As for the shift shaft detent holes a good cleaning with a rifle brush and brake clean before blasting and a steel rod the dia of the detents slid into place helps. After blasting I use soapy hot water and high pressure siphon after blowing beads off dry. Once wet they tend to cling in the worse places. After soap and water cleaning I use a couple of cans of brake clean then drop off at local auto tranny shop for a run thought their cleaning machine. They run all case parts for half a day for $20 US. A thimble of beads will ruin a $5000. rebuild in short order. Steve (CTR)

[rich@minispares.com]

While not the the answer to your question I do a lot of trannys

nice of you to share that with us!

joking apart, your right with what you say, cleanliness is godliness when its comes to mini gearboxes, I hate it when people tell me they have had the cases blasted......

[Lakeland997]

They're out!

The solution was WD40, carefully shaped stiff wire on one side and a magnetic pick-up on the other.

Thanks for all the advice. I'll think carefully about the blasting...

[ricardo]

Pretty much how I did it too. Well done. Your plunger and spring look new, are they new?

Regarding the blasting, if you go for it make sure every bit of media is removed before the assembly. As others said.

The recess below the plungers you just removed is a good hidden area to accumulate thick oil/dirt (if the box has been stored open) and the media will stick to it and you will not see/reach it easily.

Don't use sand or thick media. I've seen a box sand blasted a few months ago with deep, deep pitting. Completely useless which is unfortunate because I offered the box to the guy and told him NOT to do it.

On my box I washed it several times with celulose paint thinners and used compressed air to get rid of all the dirt. Used white paper towels to check all cavities until the paper came clean (that means no dirt for the media to stick to). After well dried, I bead blasted it with 'worn' glass bead (almost dust), this didn't hurt the alloy in any way. It took several hours. After bead blasting, it was washed again several times with a bath in warm water with detergent in between to make sure it got clean. Let it dry, compressed air again (every hole including bolt and dowel holes), thinners and finished with a good inspection (use your fingers, tools, paper, whatever comes to mind). This may look a bit paranoid and everyone has their methods, but as Steve said, a bad or rushed clean up may ruin a $5000 build.

Before


After


When you start rebuilding it, don't forget to fit the reverse spring and plunger, first thing!

[Tim]

I got my gearbox looking as clean as that by first washing it out with kerosene, then using a non-solvent parts washer/degreaser, which is mildly caustic. I was amazed at how well it lifted 50 year of oil stains off.

Tim

[Vegard]

I've never bead blasted a casing. I wouldn't either.

[Spider]

I've had some stubbornly dirty cases soda blasted, it works very well on grease, oil and paint but doesn't really touch the alloy or the machined bits. I'm not saying that it is the way to go, but does give very good results which are harmless to the casing itself.

[tedmcedd]

We have used Ultrasonic cleaning for the alloy sumps and gearboxes on the Rolls at work, Its insane how clean they come back!

No bead or shot used....

Ed