BP 51 Suspension Rebuild Process (4 Viewers)

[Sandman614]

I finally manage to get the caps off.. now here are my measurements on all the seals and wipers in the rear shocks and the closest Viton match from theoringstore

ID measured as Diameter of piece the oring inner diameter seals to

Reservoir -
IFP - oring - 5mm CS, 41.8mm ID, [5mm x 42mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]
Wearband - 8mm tall, 1.5mm thick, 48.5mm ID (Plastic?)

End Cap - Inner oring - 2.5mm CS, 46.7mm ID [2.5mm X 47mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]
Outer oring - 2.5mm CS, 49.5mm ID[2.5mm X 50mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]
Nitrogen fill valve oring - 1.75mm CS, 8.35mm ID [1.78mm X 8.73mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black (BS611)]

Shockrod -
Piston - oring - 1.9mm CS, 44.8 ID [2mm X 44.5mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]
Wearband - 7.88mm tall, 1.5mm thick, 47.6mm ID (Bronze?)

End Camp - Inner oring - 2.5mm CS, 46.7mm ID [2.5mm X 47mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]
Outer oring - 2.5mm CS, 49.5mm ID [2.5mm X 50mm V75 Fluorocarbon FKM O-Rings 75/80 Durometer Black]

 

[Sandman614]

I ended up making my own pin spanner because the one I bought from ebay, we'll you judge.. Also you'll need a 38 or 39mm 'blind inner bearing puller' to grip the inside lip of the IFP, since there is no threaded hole like other brands.

 

[Aslantarek]

While I wait on the hydraulic shop for my hoses, they said they'd have to special order the fittings..

The previous shop had a hell of a time getting these caps off and mangled the pin holes. Since they had them off, I figured this would be much less hard for me.. Or maybe they didn't actually get them off.

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you just need to torque it while opening it so use some leverage but be careful not to ruin the holes more.. well im not sure the length of the hose. but it usually takes just a little bit below a liter of oil.. but you really need to clean the whole thing well

 

[Sandman614]

I just ordered new orings for my schrader valves and saw theoringstore had this oring inspection/measuring sorcery. My oring measurements were based on the diameter of the piece they were on. This tool showed the schrader valves smaller than what I measured for a tighter fit. Olypsys | Advanced Industrial O-ring Measurement - https://olypsys.com/

 

[Aslantarek]

I just ordered new orings for my schrader valves and saw theoringstore had this oring inspection/measuring sorcery. My oring measurements were based on the diameter of the piece they were on. This tool showed the schrader valves smaller than what I measured for a tighter fit. Olypsys | Advanced Industrial O-ring Measurement - https://olypsys.com/

If you can take all the oil seals to that machine and give us definitive measures we could really wrap this whole thing up.. for every oil seal including the ones behind the rebound adjustment ring... there are 4 there 2 on top and 2 on the bottom.. i heard these 4 were proprietary by ARB iv never seen them before they are actually squared off not round.. 2 side by side top and 2 side by side on the bottom.they were 6mm thick when i measured them. when i tried to use 2 round ones instead it didnt work.. it has to be those squared off ones

 

[Sandman614]

If you can take all the oil seals to that machine and give us definitive measures we could really wrap this whole thing up.. for every oil seal including the ones behind the rebound adjustment ring... there are 4 there 2 on top and 2 on the bottom.. i heard these 4 were proprietary by ARB iv never seen them before they are actually squared off not round.. 2 side by side top and 2 side by side on the bottom.they were 6mm thick when i measured them. when i tried to use 2 round ones instead it didnt work.. it has to be those squared off ones

Since my rings weren't leaking I didn't take them apart. I've already got the shock back together, refilled, and waiting for nitrogen.

 

[Aslantarek]

Since my rings weren't leaking I didn't take them apart. I've already got the shock back together, refilled, and waiting for nitrogen.

Damn well its nice to know this machine exists i dont think i have it anywhere here where im from but oh well.. let me know how it goes then and good luck... btw the pressure is 290 +/- 15... you can go down abit if you want a plushier ride but the adjusters wont be as accurate as if the pressure is correct... make sure you just add 100 psi and leave jt for 20 mins or so just to seat everything in place then give it the full 290

 

[Sandman614]

Still waiting for my buddy to get his nitrogen setup. I decided to swap the hose and oil on the 2nd shock that the shop was supposed to get into the same as the first. I sure was charged for oil and seals for 2 shocks.. Now you tell me this oil is new with less than 1000 miles.

 

[Sandman614]

Hopefully this is the last from me on this. I bought a no loss gauge capable of 700psi($70), the wrong size 1/8npt to 1/4 flare adapter($5), and grabbed 1/4npt to 1/8npt reducer from my stash. Talked my HVAC Tech neighbor into letting me use his nitrogen. Unfortunately he doesn't have an adjustable regulator and we were too lazy to get his gauges hooked up so we over shot a little at 340psi. I figure I'll check the pressure again later and the little bit of loss(from the no loss valve) might bring them down close enough to spec.

 

[Aslantarek]

Hopefully this is the last from me on this. I bought a no loss gauge capable of 700psi($70), the wrong size 1/8npt to 1/4 flare adapter($5), and grabbed 1/4npt to 1/8npt reducer from my stash. Talked my HVAC Tech neighbor into letting me use his nitrogen. Unfortunately he doesn't have an adjustable regulator and we were too lazy to get his gauges hooked up so we over shot a little at 340psi. I figure I'll check the pressure again later and the little bit of loss(from the no loss valve) might bring them down close enough to spec.

View attachment 3776350

View attachment 3776351that is too much try to drop it alittle anything from 240 to 290 is good

 

[alia176]

This has been a great read, thanks!!!