X3 Vacuum Booster Adapter Fittings

[hoveringuy]

I've been running the X3 booster and I'm very pleased with it. One thing nobody mentions is that it is RIDICULOUSLY light, as it replaces a steel booster and MC with aluminum.

[Victell]

Stock Clevis fork from your e30 brake booster. You’ll need to cut off the clevis fork from the X3 booster and slim down the X3 rod a bit (I just took a grinder to it to shave off a few MMs). Then tap the rod to fit the e30 clevis fork (don’t remember what size I used but I’ll check tomorrow if you need). Make sure the new X3 rod/clevis extends the same length that the e30 rod/clevis did from the base of the booster also. Mine bolted right up and fit perfectly to the brake pedal

I'm also prepping for this swap. I think I've got everything I need except for threading the rod. Do you remember what size tap (die) the threads are? Thanks

[TheGreatDecay]

I'm also prepping for this swap. I think I've got everything I need except for threading the rod. Do you remember what size tap (die) the threads are? Thanks

I’m like 90% sure I used M12x1.5. Make sure you’ve got the correct adapters for the brake lines to the MC also Sent from my iPhone using Tapatalk

[hoveringuy]

I'm also prepping for this swap. I think I've got everything I need except for threading the rod. Do you remember what size tap (die) the threads are? Thanks

It was two sizes down, as I recall, so I threaded twice. First M14 to M12 and then M12 to M10. (It may also be M12, I don't recall)

There's not a lot of room for welding but if I did it again I would just cut the existing threads off and tack a new rod on.

[Chilezen]

I welded mine. Once I took out the E30 booster, I measured the distance from the center of the clevis pin to the mounting face of the booster. Then I held up the clevis next to the E83 rod, measured from the mounting face, and then marked how much of the rod I would need to cut. I cut, then did my best to hold the clevis straight in line with the rod, and TIG'ed all around it. I wouldn't trust a few tacks by themselves for such a critical component. The downside is, I melted some of the plastic, and I don't know the extent of any further damage inside.
I'm in the middle of the swap, so right now the booster is installed, but I haven't tested it yet.
Personally, I wouldn't recommend welding, but, I do want to get another booster, just to take it apart completely, to see inside, and see if I can separate the rod to weld it, and then put it back together. But I didn't because I didn't want to risk not being able to put it back together first.
Shaving the rod down to thread it seemed like too much trouble to me, but it's possible, and you don't risk melting anything.
My other idea was to weld a bolt (with the head cut off) to the rod, so I can thread on the clevis, but this has the same downsides as just welding the clevis itself.

[Victell]

Make sure you’ve got the correct adapters for the brake lines to the MC also

I went ahead and got these from the ebay store.

As you can see the M12 side is a taper fit and M10 side is also tapered for the e30 bubble flare brake line. This is very important because threads don't seal the system from leaks, the taper ends do.

[Reiner]

I’m like 90% sure I used M12x1.5. Make sure you’ve got the correct adapters for the brake lines to the MC also Sent from my iPhone using Tapatalk

Since the hydraulic lines come up a little short how did you go about straightening them out a bit to reach further?

[hoveringuy]

I welded mine. Once I took out the E30 booster, I measured the distance from the center of the clevis pin to the mounting face of the booster. Then I held up the clevis next to the E83 rod, measured from the mounting face, and then marked how much of the rod I would need to cut. I cut, then did my best to hold the clevis straight in line with the rod, and TIG'ed all around it. I wouldn't trust a few tacks by themselves for such a critical component. The downside is, I melted some of the plastic, and I don't know the extent of any further damage inside.
I'm in the middle of the swap, so right now the booster is installed, but I haven't tested it yet.
Personally, I wouldn't recommend welding, but, I do want to get another booster, just to take it apart completely, to see inside, and see if I can separate the rod to weld it, and then put it back together. But I didn't because I didn't want to risk not being able to put it back together first.
Shaving the rod down to thread it seemed like too much trouble to me, but it's possible, and you don't risk melting anything.
My other idea was to weld a bolt (with the head cut off) to the rod, so I can thread on the clevis, but this has the same downsides as just welding the clevis itself.

I love my Tig, but I think a Mig would work better here. Lots of heat and material instantly so it takes less time. I would grab the shaft with a vice grip before it disappears into the booster to help absorb the heat.

[TheGreatDecay]

Since the hydraulic lines come up a little short how did you go about straightening them out a bit to reach further?

I’m still deciding on this myself. Currently leaning on just ripping out my ABS and bending new lines myself

[Reiner]

Thanks and to the people that were asking previously the thread on the E30 clevis is M10x1.5

[efficient]

surprised no one has made a custom clevis already just to be dropped in.

[Reiner]

On the oil fluid reservoir what caps are you guys using? The cap from the M20 has a different connector and doesn't fit the X3 cap

Edit: just using the whole original M20 cap so the connector fits

[TheGreatDecay]

Motor went in today and test fit the m50 manifold. Needed the first 5-6 fins shaved down but fits solid now and doesn’t make any contact. Running Condor mounts. Sent from my iPhone using Tapatalk

[Reiner]

I have the booster and the motor in. Shaved down the fins and still can't get the M50 manifold on. Will try to lose the motor mounts and lift the motor up a bit to see if I can get it on. Revshift motor mounts

[Reiner]

How did you guys connect the vacuum line from the booster to the intake manifold?