My Bus' Rear End Is Sagging

[Abscate]

One minute of arc is 1/60th of a degree, one second of arc is 1/60 th of a minute.

Units borrowed from time. The SI unit of angle of measure is the radian

2 * pi radians , approximately 6.28 = 360 degrees
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[metahacker]

you can fit Gabriel HiJacker 49215 rear shocks
they are chrome piston gas shocks with real "bellows" style suspension air-bags over them and a steel shield over them. (basically an "air coil-over")

they are tough and work well.

the price vs quality is pretty remarkable IMO, they are very inexpensive! (yet very high quality IMO)

they are not to be confused with the monroe max-airs .. which are just not as nice IMO

i have them on 2 buses, a 69 single cab and a 78 riviera camper ..

here they are on a vanagon, fitment is similar...

(they look big and fat but clearance has not been an issue for me with 225 or 215 tires on the one side, or the frame itself on the other)

you can use, i believe, Audi bolt part N-909-24-02 for upper mount bolt.... with an extra washer under shock ear (as a spacer for alignment)
and the stock upper bolt in lower position
that is how they are on my 78 IIRC

the mounting ears are a little wider, so hence the hardware changes ..

alternatively, on my 69 i cut the shock ears down and pressed in the stock bushings from a vw OE shock.. and mounted using the original hardware... IIRC...those went on 12 years ago.... still hold air just fine

if you look at the standard OE replacement shocks (per Gabriel) for the rear of a Bus, here are the specs:

Shock Extended Length: 22.73 in. 577.34 mm.
Shock Collapsed Length: 13.87 in. 352.3 mm.
Length of Stroke: 8.86 in 225.04 mm.


here is the bagged shock

Shock Extended Length: 23.02 in. 584.71 mm.
Shock Collapsed Length: 14.16 in. 359.66 mm.
Length of Stroke: 8.86 in 225.04 mm.

you can see they are within a reasonable tolerance of each other (less than 1/3" length...and identical stroke)

you should use gabriel accessory kit # 141099 with them.. which will plumb them with independent air lines ... that way air doesn't transfer between them while cornering (acting as an anti-anti-sway-bar )

they fill/release air using a standard schrader tire valve that you can easily mount in the existing factory holes in your fender, or somewhere else clever like in the support brackets for the heater box dump tubes .. you add air to add more 'coil-over' support and remove it to reduce spring rate ... they are terrific for load-leveling or simply adding a little bit of spring rate ..

they are rated to take ~20-25 min to 200 max (!) psi ...

VW has a history of using coil overs in the rear of buses, as the single cab was rated at +0.25 tons additional load with a VW optional coil over.. so i don't consider adding them to be inherently unsafe

that said, reinforcing the mounts is always a good idea with any "coil over" (bagged shock is essentially the same)

i once have used the hijackers on my single cab to haul 2,200 lbs of concrete rubble .. easily reset to stock ride height with a reasonable amount of psi and worked great ...

you can basically dial in how high you want your rear and corner match between sides for uneven loads (like a bunch of camper stuff...i know vanagon guys use these same shocks and talk about their "westy lean" on the drivers side)

IMO bilstein front and gabriel hijacker rear is BY FAR my favorite setup for a Bus after testing stock, KYB gr-2, KYB gas-a-just and even the famous Koni adjustables

also, i believe Gabriel 49307, based on my research, fits the front if you want to get crazy adding air bags to the front ... but, i have not ran those ... and can't say much ..

and yes one should not ignore the index of the rear torsion bars .. one should be mindful of understanding / making sure they are set properly... in tandem with these variable rate coil overs

you have some useful adjustability ..... the base height of the torsion bars can be decreased/increased in tandem with adding/removing air to alter the final spring rate ...

[aeromech]

I put them on my 1971. They lasted for years. Never damaged anything. That was back in the 1980’s. Later, I pulled them and installed a new set of Bilsteins. Can’t remember if I adjusted my torsion bars but I probably did. That was a long time ago
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[Jimmunson]

We have a ‘71 bus and there is no room for coil over shocks. I thought that would be a solution too, but not on this year.

[theizzardking]

[woodyvw9]

I went on a different route altogether, when I replaced stock wheels with 15' BRM replicas I put slightly taller tires on the back than on the front. No more sag and heck I needed new tires anyways. Sort of ghetto but it worked and I did not have to do any trigonometry.

Woody
1978 Westy
1986 Jetta turbo-diesel
2002 Passat GLX wagon

[cbr900racer]

i just came in from adjusting the the driver's side rear of my 71 bay. i could not believe how easy that was! I thought doing a bug was easy. all i removed was the nut on the Ebrake cable, remove the clip that holds brake line to diagonal bars and remove the top shock bolt. That by far was the easiest i have ever done. I will attack the passenger side sometime this week. I guess they probably got alot harder from 72 on
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71 Bay (1776 in process)
94 Sonoma
98 Suburban (bike hauler)
97 Blazer
07 Nitro
94 CBR900RR (runs 5.70s 1/8 mile)

[JamesT]

[guatebus]

[steponmebbbboom]

[Micropassatman]

I have coilovers on my '70 as well. I used them primarily to keep the sidewalls of my rear tires from being cut to shreds. Seems to do the job just fine. They are not overtly harsh at all, and they reduce that 'sailboat effect' in high winds and while swimming with semis.

[guatebus]

To change the subject slightly:

How is all of this related to rear-wheel camber? I did the spring plate adjustment on my '69 a couple of years ago and the ride height looks good. However, I still have a negative camber on the rear wheels that seems greater than the spec listed in Bentley. According to the manual, rear wheel camber is largely a function of the spring plate angle...

Why is my camber still lousy and how can I fix it?

- Guatebus

[GeorgeL]

[nemobuscaptain]

OB, try Jamie Rivers on type2.com.
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[OB Bus]

[fukengruvenoval]

Just my $0.02 on coilovers...

Keep in mind the shock mounts were never designed to handle the kind of forces coilovers will put on them.

Yes, coilovers were a factory option but consider this:

1. This was 30 years ago, the mounts and surrounding metal have almost certainly degraded since then.

2. The rears didn't have a sag from the factory when the coilovers were an option. The coilovers would have worked immediately in conjunction with the torsions to add support to the rear for carrying heavy loads. Using them to raise a sagged rear end means they are handling a significant amount more weight than originally intended.

I considered it briefly on my bus but decided against it for these reasons, plus the fact the rear isn't really sagged anyway, as others point out, when there is weight in the front everything seems level.

Do a search on this forum and you'll see plenty of horror stories of wrecked shock mounts from coilovers.
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[nemobuscaptain]

Re: coilovers availability:

[Tram]

[OB Bus]

[nemobuscaptain]