Load leveler problems; 1975 Fleetwood Brougham

[Rchard Paley #1966]

From past unsuccessful experience, I rather not restore the failed load leveling system but try other means to get the car back to its proper rear height off the ground.  Im thinking of purchasing Deville rear coil springs specified for sedans without load leveler, and instlling deville gas shocks as well.  Does anyone know if this would work - or have other suggestions (would 75 Deville rear springs fit the 75 Fleetwood Brougham)?  Thanks for your help.
Richard Paley
vassi@optonline.net

[David #19063]

Hello Richard,

Unless your rear springs are bad, you would not need to replace them.

The DeVille springs probably would not be the right strength.

Just get a set of air shocks and install.  

The 68 Brougham I bought that was restored was set up this way.  They just drilled a small hole in the trunk and mounted the stem inside.  

The 94 Brougham I just bought is set up the same, but they put the stem outside...Id prefer it inside.  

Good luck.

David

[Richard Paley #1066]

Thanks for responding, David.  However, I had poor luck with air shocks when I did a similiar conversion years ago.  I was thinking of installing K-Ds gas shocks for 75 Deville.  Any thoughts on this?  Thanks, again.

[Bruce Reynolds # 18992]

Richard,

Normal acting shocks, and even gas filled ones wont restore ride height.

I woulod be talking to a suspension shop or spring works to see what they recommed.

And, there is nothing wrong with purchasing a pair of air bags that go inside the coil springs.

I have done that on a couple of cars, and it is surprising just what a difference they make.  

But, it is necessary to install individual airlines and valves to each one so then you can "tune" it.

The problem with a "common" airline is that as the vehicle turns a corner, the air can transfer to the inside as the outside bag, or shock, compresses.   This will unstable the car as the inside is being lifter higher.

Bruce,
The Tassie Devil(le),
60 CDV

[Robt.Vonheck -via SunDiego Calif.]

--yes, be sure to heed Brucies Safety-advisory, if just running oem-type/airlift-shocks (without use of the preferred oem/Air-pump & Leveler-valve) absolutely DO NOT employ a T-fitting to a common fill-valve in the trunk or fuel-flap area; --you have to separate the two sides much as the specially engineered original oem/Leveler-valve split the two sides into discrete(separate) air-lines;  --otherwise the car will not corner properly and will wallow on the road!  Those of you still alive yet employing a T-fitting, need to remove the T-fitting asap (do not rest nor attempt to drive the vehicle until this is attended to)!  Our thanks to the ever thoughtfully vigil if ubiquitous TassieDevil for reminding us of this common installation oversight, which can impose dangerous handling under various conditions, -by its enabling say 90-psi/line-pressure to flow into the inside air-shock instead of to the outside/Air-shock when entering a turn (thus adversely exaserbating the normal tendancy of the car to lean in a turn you see; --taking this to extremes by way of further understanding, an ideally stable air-system would actually pull-down the inside/air-shock via suction, or at least entirely negate the air-pressure to the inside/air-shock while entering a turn)...   ~Bob vH  

[Steve Preston #16375]

Richard,
But, it is necessary to install individual airlines and valves to each one so then you can "tune" it.

The problem with a "common" airline is that as the vehicle turns a corner, the air can transfer to the inside as the outside bag, or shock, compresses.   This will unstable the car as the inside is being lifter higher.

Bruce,
The Tassie Devil(le),
60 CDV

Bruce, Are you implying that this happens with air shocks as well? If so, then why have they been installed for so many years? Im not being argumentative, just curious.

Steve

[Bruce Reynolds # 18992]

Gday Steve,

Now, as for the reason that the installers install a "common" filling point, well, it is done for simplicity of the installation, and for the simplicity of the operator.   They only have to access one point, and dont have to be particular of balancing pressures as the two units balance themselves.   Plus, if there were two points to check, then it would be possible for the uninitiated to check one, and forget about the other one, and even worse handling problems could occurr.

The reason most pump-up shockers and air bags are fitted is for load carrying, and as most drivers dont really care about what goes on with the mechanicals of their choice of transport, dont really care.   All they want to do is drive from point A to B, and carry that load in the back.

The problems are most noticeable in a higher performance vehicle, but, there is nothing wrong with being safety concious, and a 2 ton plus car that handles better, makes for a safer car on the roads, and the driver also feels safer.

Having said that, to have individual valving, allows the operator to change pressures on either side to account for variations in loading, passenger location and size, and believe me, a large passenger on one side, will affect the handling when going around left and right hand corners.  

It doesnt take much movement on one side to transfer the air pressure to the other side, and in a vehicle of Cadillac size, and traversing a high speed bend, the car will lean further, than if it had standard shocks or bags.   The Cadillac Load equalising system is designed for keeping the vehicle level on the roads with a load in the back, not to assist in going around corners.  

When I do an installation, I make sure that the valves are mounted next to one another, clearly marked, and then it is easy to individually inflate or deflate, whichever is necessary.

Hope this adds a bit of light.

Bruce,
The Tassie Devil(le),
60 CDV

P.S.   When routing the lines to the rear of the car, I bend up 3/16" brake line to follow the selected route.   Flare the ends, then slide the airline inside the tubing to so that it is supported and to protect the nylon line from being damaged.   This pipe is then clipped to the chassis or the body so it cant vibrate.  

[Porter 21919]

Having read this entire thread I thought I was on the wrong forum, this Load Leveler topic is technical in nature.

I hope the technical forum only guys check the general forum once in a while, I read both, my hunch is that the vast majority still do.

If you arent aware of the collapse posts option go to the upper right corner and give it a click, then you dont have to wade through all the subjects with messages that dont interest you.

Porter

[Richard Paley #1066]

Bruce,  
Im going to follow your suggestions for installation of dual air lines, and very much appreciate your sharing your knowledge and experience.  Do you think the "ride" with air shocks as youve installed them, is comparable to that with the original load leveler system?

[Randall McGrew CLC # 17963]

Richard, my 1977 has the Auto Level system which has long since been disconnected. However, I have the Monroe air shocks and it rides marvelously.
I am sure Bruce is a much better technical source for this but I wanted to add my two cents.  Be sure to have the springs tested.  These are heavy cars and mine were worn, so replacing those really helped.  Now I am trying to determine the correct level to set the car.  22 pounds per square inch is too high although the default inflation level.  

Eventually I want to replace the ALC with a new compressor and sensors.  They are available though not original.  I like the idea and think with current technology we could restore the system efficiently.  

Incidentally, there is a great article on the ALC in the 1977 Serviceman.  Those articles have been a god send.

[Richard Paley #1066]

Thanks for responding, Randall.  You mention a replacement system for the load leveler.  Could you tell me the source and contact info?  Thanks, again.
Richard Paley

[Mike #19861]

 Sorry, I have to categorically disagree with this whole theory.

 First of all, ALL factory systems employ a single line that shares the pressure between both shocks. They have right from the beginning in 1965. Also, all aftermarket systems use a single valve with a T fitting that shares the pressure between both shocks.

 And, all (with few exceptions) heavy trucks with air ride suspension use a single leveller valve that feeds all the airbags in the system from a single scource. These support the entire weight of the truck over many axles and there is never any concern over tipping or excessive leaning on corners. This has been the norm for decades. Even the big heavy floats use this same system.

 Now, if it is as dangerous as you feel it is, there would have been constant carnage on our highways, or all these factory  and aftermarket systems would employ 2 differant valves, one for each side of the car, and more importantly, so would all trucks.

 Now, for the few trucks and trailers thad do use a separate system on each side, they are more grief than they are worth. They rarely ride level, and setting the systems up to be level is an ongoing chore. And, if one side loses pressure, then the unit will tip dangerously to one side, whereas a single supply system will simply drop as a unit and remain level and stable.

  Mike

[Bruce Reynolds # 18992]

Richard,

Funny thing but I have never driven a car with the automatic load-levelling, that worked, so I cant comment on the ride.

But, the problem that I have with pump-up shock absorbers is that unless the vehicle was fitted with shocker mountings designed to handle the dual purpose of Pump-ups, then pump-ups shouldnt be fitted.   Cadillacs that were available with a Load Levelling System should have those strong mounts.

You see, Shockers are designed to do one thing, and that is to absorb the "shock" of the suspension movement, and to stop the "bouncing" after the initial compression or rebound of the axle.   The Springs are designed to carry the mass of the vehicle and compensate for undulating roads to make the ride smoother for the passengers or load carried.

Now, to incorporate a load-carrying capacity to the shock absorber mounting is going to make the mounting point become stressed in some cases.   Especially in the case of a monocoque constructed vehicle.   It isnt uncommon to see shocker mounts ripped out of the floors of vehicles where the top mount is to the floor.   That is where I prefer to see either air bags inside original coil springs, or assist bags installed, or extra leaves installed in the case of leaf suspension.

Bruce,
The Tassie Devil(le),
60 CDV

[Bruce Reynolds # 18992]

Gday Mike,

Yes, you are correct in what you say, especially in the vehicles that uses a total air suspension system, as in the trucking industry.

But, I was referring to the use of pump-up shocks where they are only an "assist" to the normal suspension.

For "normal" driving on straight roads that seem to be the norm in USA and Canada, a single line isnt a problem.

But, for driving on the beautiful windy roads in Tasmania, at a "driving" speed, Mulholland Drive is like driving on a freeway.

Bruce,
The Tassie Devil(le),
60 CDV

[Mike #19861]

 Hi Bruce,

 The independent action of each shock could work better than them being tied together, particularly on a winding road. But, I was in disagreement with the dire warning against them using a T fitting. There is no safety concern here.

 In Northern Ontario, there are several winding roads in which I have driven my air shock equipped Cadillacs at speed that are perhaps a bit more than recommended by the authorities with no adverse effects. If handling qualities are the ultimate desire, then more ambitious attempts att suspension modifications would work better.

 I see no harm, and do see the benefit of each shock working independent of each other though. It will be a bit more aggravating to fill them and get the same height on each side. It would wear pretty thin on me after awhile.

  Mike

[Randall McGrew CLC # 17963]

Richard, I think many of the parts can be found at USA PArts Supply.  Kanters may have some of the parts too.  The thing to do is figure out which parts are failing and see if you can replace or modify those.  The compressor should be no problem as modern versions are smaller and plenty powerful.  

The big piece is the lever / release-fill part above the rear axle.  When the car settles it presses on the lever which opens the filler side, activating the compressor until the car rises high enough to release the lever.  When the weight its removed from the car, it rises causing the lever to press on the axle beneath, opening the release valve until the car levels out again.  I think its a wonderfully simple system.  I hope that I have this right.

Apparently there are adapter kits that can be used with the newer shocks like the Monroe that will allow it to do the work.  I have yet to find this piece but I am told it is available.  At the very least, it should be modifiable.  I will post more as I learn it.  I really want to get my 77 Biarritz to work.  

Also...do a search on the CLC Forum for automatic level control and other key words to see what has been posted previously.  ALC, air ride, air shocks and automatic control are all good starters.

[Randall McGrew CLC # 17963]

http://www.cadillaclasalleclub.org/cgi-bin/user/forum.cgi?pview=flat&select=2Fclc2Fclcgenl2F525842F52600

This was helpful when it was pointed out to me again...

[Dave MacGregor #18998]

Hi,

I have a 77 Eldorado which has a fully functioning ALC system now and am completely at ease with having it on my car- the comfort of the ride, and the servicing of it that I had to go through to get it working in the first place was easy and worth it.

Yeah you guessed right.  It wasnt always working. In fact, it hadnt been working from roughly the mid 80s until three years ago when I got to fix it myself.  It really wasnt hard to fix because most of the details are in the factory service manual.  Basically all that was involved on my car was replacing the air lines, new rear Delco air shocks to the ALC system, and a rebuilt pump which I found on eBay from member "alcfx."  The whole thing took a morning to do.

I will have to add that I heard that parts for the the vacuum powered compressors are extremely scarce and so I was perhaps one of the last lucky ones to purchase a good professional rebuilt unit, but it is possible to take parts from a couple units to make a one good one as I was considering.  Again, the factory manual tells how they are assembled.

Finally, If youre not lucky enough to find a rebuilt compressor, then why not take the old one apart for fun since you cant hurt anything not working anyhow.  The problem could be as simple as replacing a bad O-Ring as I found in hindsight with my old unit.  (Later I donated my old "fixed" compressor to the owner of a 73 Eldorado whos unit was removed years ago.  That was two years ago and their system is still working just as reliably as mine!)

Anyhow, What Im getting at is the vacuum compressor ALC systems of the 70s arent that difficult to work on.  In fact theyre so simple its amazing.  Just do a little exploratory work with it using the factory service manual before giving up.  Besides, when standing by the car, its neat to hear the compressor "tick" while doing its thing.  Its that "little extra experience of the 70s automotive era" thats lost with the use of electric compressors.

Good Luck!  Have Fun!

Dave

[Bruce Reynolds # 18992]

Mike,

I dont know what sort of systems the trucking industry in USA uses, but here in Australia, all heavy vehicles using air bag suspension are fitted with a system of valvings that react to cornering movements and open to inflate the outside bag, deflate the inside bag, and then do the opposite when going around an opposite corner.

This system is constantly inflating and deflating and each bag is acting as a separate unit.   The valving is controlled by a rod at each bag and is fast acting.

If one bag blows, that side of the axle will collapse down to the stops till it is replaced.   The vehicle can still be driven, and as most vehicles using air bag suspension are of the Tandem Type, the remaining bag assists to hold up that side.

It is then up to the driver to drive accordingly.

A mate of mine had a left bag blow once when fully laden and said that he could really steam around left hand corners, but had to take it easy around right handers till he got back to base where it could be repaired.

I initially had a "Common" system on my 37 Chev Hot Rod, but changed it to individual fittings after a few runs through the Slaloms at a club day.

Bruce,
The Tassie Devil(le),
60 CDV