100 series ride quality after manual suspension conversion

[moody1972]

I recently changed to standard shocks / coil springs due to continuous problems with the auto height control in 1998 land cruiser HDJ100 (4.2 Diesel), the change involved replacement of all 4 shocks with standard hydraulic shocks, and the coil springs to hard and stiffer coil springs. The coil springs were changed because the original coil springs didn't take the vehicle weight and it would drop to lowest height on standard shocks. After harder and stiffer coil springs were installed from a non AHC LC the vehicle came to a reasonable height close to the N position but the ride quality has gone done and has become harder. My current experience on slightly bumpy roads is hard and noisy but on motorways its quite OK. I also suspect my vehicle height to be lesser than other similar vehicles after this change, Any suggestions how to improve this situation ?

thanks
MM

 

[Mxndrnks]

do a bearing repack and check your body mounts. Being a 1998, you may also want to look at this thread in the FAQ:
https://forum.ih8mud.com/100-series-cruisers/509016-200k-make-over.html

 

[spressomon]

What is your ride height as measured from the center of the hub straight up to the lower lip of the fenders? Its also possible the hydraulic style shocks are less compliant too...

 

[moody1972]

thanks for the reply, One question in my mind which is not clear because of my lesser 4x4 experience is that whether the front height and the rear height of the vehicle should be same ? is there any standard height which should be done on 100 series ? does raising the height of vehicle provide a smoother ride or otherwise ? as i see the front end of my vehicle is lower than the rear end, is it also contributing to the bad ride experience ?.
thanks

 

[FullyLitLED]

thanks for the reply, One question in my mind which is not clear because of my lesser 4x4 experience is that whether the front height and the rear height of the vehicle should be same ? is there any standard height which should be done on 100 series ? does raising the height of vehicle provide a smoother ride or otherwise ? as i see the front end of my vehicle is lower than the rear end, is it also contributing to the bad ride experience ?.
thanks

Smoother ride by having level I cannot speak for but I think there is a 1" rake from the factory. Some people have 0.5" rake and some 0.25" rake so it is up to you what you want to do. We have a lexus with AHC and I can tell you that I am not a fan of the ride quality when it is set at max height...

As far as the ride quality after the lift on a 100 series, that is also based on preference. What may be hindering your ride quality is you may be expecting it to ride like the stock plushy 100 series When I went from stock to 866's I felt the truck was stiffer in the ride department but the handling was a lot better. People say the 863 will be too "stiffness" much but I have those and I feel the truck handles even better than when it had 866. If there is any difference it is not in a negative manner. Of course I have a rear drawer system in the rear so that could have affected the results.

It is all based on your personal preference and definition of "good" ride quality!

Good luck!

 

[Mxndrnks]

Yeah there is a lot of personal feelings when it comes to ride quality. But, there is definately some affect when refering to wheel pressure, ride height, and rake. In general, most people have found that you want at least 1" rake from front to back. I.e the front about 1" lower. The way the truck is designed just seems to want to be this way. As FullylitLED is pointing out, some people go with less rake and are ok with it. But it will affect ride quality. Also, spring and shocks will affect the ride as well. Before we go further in trying to help, it would be best if you could tell us a little more about your ride. What shocks, springs, did you lift it? heights measured from center of hub to fender on all four corners, what tire pressure are you running, what tires, etc. All these things can have an impact.

 

[moody1972]

What is your ride height as measured from the center of the hub straight up to the lower lip of the fenders? Its also possible the hydraulic style shocks are less compliant too...

hi

right side fender to hub center = 45mm
left side fender to hub center = 45mm
right side rear fender to hub center = 47mm
left side rear fender to hub center = 49mm

Tyres = Yokohama Geo-lander H/T-S
RIM = 275/70/16
Air pressure = 33PSI on Tyres
All 4 non AHC toyota genuine hydraulic shocks
NON AHC Coil springs

thanks
MM

 

[agaisin]

hi

right side fender to hub center = 45mm
left side fender to hub center = 45mm
right side rear fender to hub center = 47mm
left side rear fender to hub center = 49mm

Tyres = Yokohama Geo-lander H/T-S
RIM = 275/70/16
Air pressure = 33PSI on Tyres
All 4 non AHC toyota genuine hydraulic shocks
NON AHC Coil springs

thanks
MM

What about torsion bars - are you still using your ahc torsion bars? If so that could be a contributor, I think. Not only were your old tb's tired but te ahc ones are designed for ahc an should be swapped out for non ahc tbs when doing the swap based on my understanding.

Also what about sway bars etc. For sure you could use sway bar bushing refresh if it hasnt been done. not sure if non ahc and ahc sway bars are the same though - that may also need replacing if non ahc ones are thicker/stiffer.

also - when you talk about ride comfort - how would you describe your complaints? side to side swaying, bounciness, harsh over ecpandion joints, problem all the time on all roads or only on curves or only on bumpy roads etc.... might help people troubleshoot a bit.

 

[moody1972]

yes old AHC torsion bars are in use and not changed so far.
Sway bar refresh done was done with recent suspension works.
harsh over ecpandion joints & only on bumpy roads, fine on motorways and smooth roads


thanks

MM

 

[agaisin]

yes old AHC torsion bars are in use and not changed so far.
Sway bar refresh done was done with recent suspension works.
harsh over ecpandion joints & only on bumpy roads, fine on motorways and smooth roads

thanks

MM

hrsh over expansion joints seems to be common when wheel bearings are the issue. i think someone else suggested it already but i'll second that - check for play in wheel bearings and at least open it up to tighten em if needed but perhaps a repack would be in order.

tb's new are actually expensive iirc (discount proce over $300 each). u could get em from someone else with reasonable miles that just swapped out oem...

 

[spressomon]

hi

right side fender to hub center = 45mm
left side fender to hub center = 45mm
right side rear fender to hub center = 47mm
left side rear fender to hub center = 49mm

Tyres = Yokohama Geo-lander H/T-S
RIM = 275/70/16
Air pressure = 33PSI on Tyres
All 4 non AHC toyota genuine hydraulic shocks
NON AHC Coil springs

thanks
MM

These measurements should be something like 19-21" for the front (482mm-533mm) and 20"-22" (508mm-558mm).

Here's where you should be measuring...

 

[moody1972]

Thanks. I have noticed that my lc rear jumps hard when i drive over speed breakers, is it due to the oem shocks or the used coil springs from a non ahc lc100
thx

 

[Brock]

sounds like you dont have enough weight in vehicle for springs you installed yet...so the springs are pushing up hard.

ride is going to be different....not going to have a plush ride when you replace AHC that is working properly with standard offroad setup. E rated tires....higher pressures....shocks and springs made for rough terrain and heavy loads.

Compare it to a stock Lexus and you wont like it. Compare it to a similar Land Cruiser, Jeep, etc with offroad suspension and it is fine.

I notice the small cracks and stuff more now but offroad and over big stuff it is great. I prefer the more solid handling in corners and better weight capacity now to the "cadillac" ride....if I wanted that I would have left it stock and not put on E Rated Trail Grapplers.

 

[moody1972]

Thx for the comments, since i drive 90% onroad and 10% offroad so i am still wondering whether it was a mistake to remove ahc due to its frequent problems? Can i still improve to a plush ride using my existing non.ahc shocks and springs? Should i get softer coil springs to improve the rear side jumps or move back to ahc shocks since i have not removed ahc components ie sensors and fittings completely. Personally i love smoother and plush rides as this is my first experience with a 4*4 so maybe experience will change my mindset. The conversion to non ahc+ suspension work costed me roughly $3000 already so i am keeping my fingers crossed what it might cost additionally. All suggestions are welcome


Thx
mm

 

[lpj23]

I personally prefer the plush ride of ahc but if it becomes troublesome, I would switch to standard suspension using all toyota parts...tbars, shocks, coils. You can probably double check if the coils you used from a non ahc 100 are indeed toyota stock coils and not old man emu or other aftermarket coils. With original stock coils, the ride will indeed be a bit harder but should not "jump" over speed barriers. Also check out if you can get stock tbars from those who replaced with aftermarket. The tbars from ahc may have difficulty carrying the 4.2 diesel beast. Good luck!

 

[Brock]

you can likely get stock shocks, tbars, coils that are put on the non-AHC vehicles and should give you a good ride...maybe not as good as a fully functioning AHC but better than an Off Road ride.

That is what I would do if you want ride comfort ABOVE weight and offroad potential....

Then sell your offroad items to someone on here that wants them...

my two cents....

 

[RL4x4]

As someone who has owned a 2001 LC with two different suspension set-ups and now a 2007 LX470 with the stock AHC system I have to say that the AHC system rides far better and smoother than the LC ever did. Unless someone is A) a hardcore off-roader and needs a big lift or B) can't afford to fix a broken AHC system I would never recommend removing AHC.

 

[Brock]

^^^^Agree. If my AHC would not have started falling when parked and having to readjust itself at every stop light from the heavy bumper/winch up front and tire/hi-lift/bumper out back...I would have left it in.

It ran great offroad in HIGH setting...and normal was a pleasure especially on comfort setting. It is a great system if maintained....

 

[moody1972]

I got the new coil springs today and the rear side of vehicle was substantially higher than the previous height after installing them, afterwards i managed to raise the front height by adjusting torsion bars and the result was a far better ride experience, so this solves my current ride quality issue. I am sure with ahc the experience would be far better but i am happy with the current result so thanks to all for the help. I would however appreciate if someone can advise me on any potential risks of running on standard shocks and springs if any on a ahc LC
Thanks

 

[lpj23]

I got the new coil springs today and the rear side of vehicle was substantially higher than the previous height after installing them, afterwards i managed to raise the front height by adjusting torsion bars and the result was a far better ride experience, so this solves my current ride quality issue. I am sure with ahc the experience would be far better but i am happy with the current result so thanks to all for the help. I would however appreciate if someone can advise me on any potential risks of running on standard shocks and springs if any on a ahc LC
Thanks

As long as installation were all done correctly, you're good. Im just not sure how long the tbars will last if you're still using the ones when you had ahc. What rear coils and shocks did you use?