Another LS Swap: L92 & 6l80e into a '94 LC

[Tinkertoy]

Just rolled 10k on the swap so must not have made any critical errors. Hadn't been totally thrilled with the brakes since the swap. There was slack to take up and seemed like a delay to application of full power. (Plenty to lock them up on dry pavement.) I finally decided to address this. Went ahead and ordered a reman'd hydroboost unit to replace the one I'd pulled from the GMC Safari. As I inspected the junction btw the HB unit and the Master Cylinder, I discovered that the pin/rod in the HB unit was too short. Through multiple measurements and a little trial and error, a friend of mine machined a new rod for me. We turned it out of a 3/8" grade 8 bolt. The picture will help, but the picture isn't totally accurate. The OAL of the rod needs to be 3.60", not 3.50". Unlikely to help anyone unless they use a '93 Safari HB unit and mate it to a '94 Landcruiser MC. For what it's worth, the brakes are 100% better with a new HB unit and an appropriately lengthened rod.

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My brakes seem okay at best after the swap.

I replaced the calipers with Amazon units. (This could be my issue). I had one bad spot in my brake line which I replaced. My pedal seems to go down pretty far before brakes start to work.

My assumption could’ve the calipers as I have leaks. At least not brake fluid. I have about 12k on this swap.

I just don’t know brakes well. What kind of options would I have to make this beast stop better?

 

[Scalpel]

I can give a little feedback on this, but I'm not sure it's sound advice so I'd ultimately defer to someone with more experience. I initially took the vehicle to a Toyota dealership because I couldn't get all the air out of the lines. (I was doing a 2-person bleed. One pumping then holding pedal, one cracking the nipple.) Pedal was just too squishy for my liking. The Toyota dealership bled it (not sure exactly how - vacuum? +/- ABS activation?) but it still wasn't right. I found that immediately after I activated the ABS on an icy road, the brakes would feel solid for a bit but over time, they'd get soft. I got to wondering if the ABS system was taking a large bubble and making a bunch of tiny bubbles that were less compressible. Maybe that doesn't stand to reason, but I couldn't come up with a better explanation. Anyway, I put the vehicle on jack stands, got the speedo up to about 20mph and slammed on the brakes. ABS activated. I then immediately bled out one corner with the help of a friend. Repeated process three more times and problem solved. Hydroboost helped, but until the air was out of the lines, it would have still been a soft pedal.