Coil springs for AHC

trdcorolla

SILVER Star
Joined
Sep 25, 2016
Messages
1,458
Location
Los Angeles, CA
I do not see a difference in part numbers between an 06 LX and my random search of an 03 LX.
RH 48231-6A730
LH 48231-6A740

I was expecting the pressure to drop more than it did. I will perform the flush and see what that changes.
Since the springs vary pressure and I am stock with new OEM springs, then I really should not be looking at this with a magnifying glass. I think it's very close to how it would have been when it first rolled off the floor.
Also, the verbiage in the FSM makes me think there is % error in reading when using the "hand-held tester" compared to the gauge. "The cylinder pressure read by the Lexus hand-held tester is estimated by the pump emitted pressure so the pressure is approximately 1.2MPa higher..." This may be the reason why results vary between vehicles and users. I would be curious to compare results with the LSPV gauge (SST) since it would be live pressure and not estimated. Anyone have one of these tools?

View attachment 2650765
I was comparing the LX AHC springs that luckily weren't available when I needed them to the 06/07 Land Cruiser AHC springs that I purchased instead. It was actually on this thread that someone said the RH Landcruiser AHC springs were used in Australian 100's that came equipped 2 gas tanks, hence the assumption of a a higher spring rate. Below are the part numbers I was referring to.

RH 48231-6A770
LH 48231-6A780

I agree with you saying you shouldn't have to deal with this since you are replacing old with new oem, but unfortunately that's not the case with some people of us. Some here are in spec with the temp sensor unplugged on 15-20 year old springs, it looks like both of us were in the opposite camp. Have you gone through the thread:


I learned a lot reading through that whole thread, if you need cliff notes version of it, you can look at this thread:

 
Joined
Jan 21, 2017
Messages
538
Location
SF Bay Area
another King pressure data point:

finally got around to plugging my LX into Techstream after the King spring install.

Before the Kings my rear pressure was up in the high 7.0 range with my ARB bumper, roof tent, rack, and drawer setup in the back (200 lbs ish)

Now with the Kings:

Front pressure: 6.3 Mpa
Rear pressure: 5.4 Mpa

pretty happy with that. It's actually a little under the factory pressure , but should be well within spec once I load up to go camping etc.
 
Joined
Sep 23, 2020
Messages
14
Location
phoenix
Again thank you IndroCruise for the information. I'm doing other things now but did want to acknowledge your reply. When I get back to the project and before the swap I will search for measured lengths of the -6A730 and 40 springs.
Because this information wants to be free I will again answer my own post with some data.

For my 2004 US LX470 w/AHC posting photos of new rear springs:
RH 48231-6A730, Yellow painted mark, length approx 17 1/2 inch, and
LH 48231-6A740, Green painted mark, length approx 18 1/8 inch.

Thanks to Desert Toy Shop in Mesa for the photos during the swap I paid them to perform.
Somewhat thanks to the dealer who reimbursed me for the swap after I confronted them again with photo documentation.

IMG_4209.jpg


IMG_4210.jpg


IMG_4211.jpg
 
Joined
Sep 3, 2020
Messages
67
Location
Portland, OR
I just put on 80 series used springs ($80) with a 30mm spacer and 1/2 loaded up pressures went from 9+ to 5.1. RTT, bumpers, 2x swingouts, 4 passengers.
and I can still get into L, N, H - thats mostly loaded though. Without the bumpers, RTT and swingouts I think maybe not.
 
Joined
Dec 24, 2012
Messages
93
Location
Nashville Tn
Thought I'd add a question to refresh this thread. I've noticed everyone replacing rear springs but not the front. I have noticed a harsher reaction and sound to bumps in the road coming from the rear of my 98 LX even after full globe replacement with fluid bleed and replacement but figured the fronts also have 356k on them so should be replaced as well.
I've also replaced front 2 AHC and 1 rear AHC sensors after my drivers side broke. Hoping to do a sensor lift of no more than 2" in the front so figured new springs would help keep less stress off the AHC.
Just wondering why more folks dont replace the fronts as well.
 
Joined
May 1, 2016
Messages
420
Location
san diego
Thought I'd add a question to refresh this thread. I've noticed everyone replacing rear springs but not the front. I have noticed a harsher reaction and sound to bumps in the road coming from the rear of my 98 LX even after full globe replacement with fluid bleed and replacement but figured the fronts also have 356k on them so should be replaced as well.
I've also replaced front 2 AHC and 1 rear AHC sensors after my drivers side broke. Hoping to do a sensor lift of no more than 2" in the front so figured new springs would help keep less stress off the AHC.
Just wondering why more folks dont replace the fronts as well.
For me, my pressures remain in normal limits with an aluminum front bumper. Most of my additional weight added is in the back. Adjustments can be made with the torsion bars. I know of a few threads with people having to change their torsion bars due to added weight in the front; steel bumper, winch, 2nd battery.
 
Joined
Jun 25, 2006
Messages
629
Location
Ridgefield, WA
I added used torsion bars from a non-AHC LC to my LX after I added the bumper and 90lb of winch antilevered off the front of the frame. I may have been able to torque the torsion bars far enough to level th pressures, but the bars were available from another cruisers lift and figured it would be easier to get the desired pressures. 5+ years later, it's worked pretty well.
 

Users who are viewing this thread

Top Bottom