308 Rear Suspension Rebuild with Pics

That is awesome - Looks great!

Makes me want to move to MA, just to be near Verell!

Good job guys.

 

thanks a lot guys now you have me going on about when to start my suspension rebuild!! its so nice to see these things clean!

 

Hey Birdman,

nice pics. Excellent write up. In my opinion, I wouldnt think it would make a difference whether the suspension was loaded or not. the bolts are orthoganal to the direction of loading. they are purely in shear. torque em down and recheck them after a few rides.

I wonder if energy suspension has bushings for the TR.....

 

Bill,

It is not the bolts that are the concern, it is the bushes. Rubber bushes (as I am sure you know) have bonded steel inner and outer liners. The bush works by the rubber part flexing as the suspension moves up and down. Thus if you tighten the bush bolts with the suspension NOT in the normal sitting position the rubber bush is under unnecessary stress ... and thus will wear out very quickly, and also make the suspension movement not as compliant as it should be.

Thus you should always tighten rubber bush bolts when the car is on the ground after a couple of bounces to ease the suspension into the correct position. I remember my father teaching me this

Pete

 

Well done. I'm doing all four corners on my car this winter. There is no baby in the house so I'll be plating the fasteners and changing the wheel bearings while I am at it.

 

You guys ROCK! Nice job, great information!

 

What a great write-up!! Well done. I'm just finishing the same job myself and after reading the acticle I believe I'll go back and weld the inner bushings. I had used Lock-Tight.
I am still undecided as to whether or not to do the hub carriers. Any insight??

Thanks in advance.

Steve Schroeder

 

Jonathan,

I'm curious about whether you needed to use anything to dissipate the heat from the welding process in order to keep the polyurethane bushings from melting? I would suspect that heat might be a problem with stock rubber bushings but not the polyurethane. Also, I'm unsure about torquing process once the bushing have been installed. Are you trying to obtain the full weight/load of the car on the bushings before torquing or is it sufficient to have something less than than?

I agree with the others, this was an outstanding post. Also very inspirational for us do-it-youselfers. Congratulations on a job well done!

 

Yes we did!
Jonathan was standing by with a very wet cloth to lay on them as soon as I lifted the torch away. Definitely could see a trace of melting beginning.

I STRONGLY RECOMMEND using:
Eastwood's Anti Heat Compound or their Form-A-Shield Heat Absorbing Gel - (It was getting late & I forgot that I had Anti-Heat compound - DUH.)

Actually, rubber tends to withstand heat until it begins to char & burn while poly tends to melt first.

Yes you want the full weight. Ideally you'll also have with the gas tank about 1/2 full, and the driver's weight in the driver's seat. (Perf. shops keep sandbags to simulate the driver!) That way under 'average' load the inner bushings aren't being flexed. This provides maximum bushing flex in both up and down deviations from the 'average' position.

Many shops don't bother simulating the driver's weight, and the gas tank is at whatever level the car drove in with.

 

Steve,
I recommend making that call after you've cleaned up the existing hub carrier components and can determine how much they're worn. If there is noticeable scoring or just plain loose fitting then replace them. Otherwise, lube them with a moly based bearing lube & re-assemble.

 

Birdman, thanks for your time and effort in making this great thread.

Some questions -

Are you happy with the results? Has the knocking noise gone?

Do the energy suspension bushes squeak? Cos if they do, it would drive me crackers and I would prefer the rubber.

I know 20-30 year old rubber bushes look cracked and frayed around the edges, but is it these that cause the knocking, or just the dampers? Did yours have wear and play in them? (Speaking as a lazy bug*er who would rather just change the shocks..)


PS - I would also like to live near Verell

 

Someone was asking about welding the bushes, this is a copy of a message to the Ferraritech list. You MUST weld the bushes. They do move longitudinally, as well as axially. Under braking, the torque allows the unlocated arms to slide in relation to the bush (Especially at the top). If you want to try it, just chalk the bush and do one quick lap of your favourite circuit and have a look. Additionally, the bush must NOT be allowed to rotate in the arm and if it does, it will gradually enlarge the hole and pull right out of the arm (Yes, right out the end) leading to catastrophic results. I know this from first hand experience when the original mechanic on my car didn't weld the bushes in.

When you weld the bushes in, you must also make sure that the "Flat" of the
bush site up hard against the side of the suspension arm. I made a small
jig to ensure this and would be happy to post pics if you wish. Finally,
locate the new bushes in the forks with new fasteners (You are going to
replace the fasteners aren't you?? and make sure it's 12.9 tensile metric
fine thread) and perform this task with the suspension compressed.

Carl.

 

RE: SQUEAK
Poly bushings that are rotating on a metal shaft are the ones that sometimes squeak (ie: Anti-Sway bar bushings). BTW, a shot of graphite or a bit of grease stops it.

The 308 A-Arm bushings are basicly two concentric metal sleeves with the poly cast in between them. The outer sleeve is welded into the A-Arm, and the inner sleeve is clamped immovably by the bolt thru the mounting bracket.
The bushing operates by flexing the poly, not by rotating it on a shaft. Hence there shouldn't be any sound whatsoever. If there is, then something's loose that shoudn't be.

 

So, it looks like with either rubber or poly, we need to do the final tightening with the A arms in their "loaded" condition".
Many of us do not have a hoist, so we will be doing this on the ground - sigh.
Is it practical to take a measurement from a pivot point to a bolt, or what ever prior to disassembly while the car is on the ground to establish what the physical relationship is between the arm and the chasis, esentially establishing what the loaded height is, so that we may position the arm at that measurement after bushing replacement, thus we may tighten the "new" pivot bolt with 0 stress on the bushing.
I am guessing it will be easier to do the final tightening without the tire or hub carrier in position.

If I may ask again, does anyone have recommendations for realignment specs differing from stock??
This assumes:
16 x 7 - 8 inch wheels with perhaps 50 series tires, (less compliant and camber insensitive than the original 70 series tires which it was designed to "work" with.
A more aggressive driving style than ferrari originally intended e.g. 4-5 track sessions per year with "street" tires.
Stock ride height & shocks, since the car must be both driven to these events and traverse bad roads and driveways.
Stock sway bars. This will likely change after I have a chance to do the brakes, wheels, etc - but we must have some basic assumptions specified to consider a change.

Being totally new to the car, I am inclined to start with stock and give it a bit of negative camber up front, (isn't positive camber some type of crime against nature???), stock negative camber in the rear and reduce the toe in to a minimum, F&R; and maybe try reducing the front castor to 3 degrees in an effort to lighten up the steering at low speeds. I could be totally out to lunch on this.

I am really having a lot of fun getting into the car. I am also appreciative of the time youall are giving to evaluate and respond to my questions.

Thanks,
chris

 

What you can do is measure the height of the outside of the rearbrake discs from the ground & stack up heavy 2x10, or heavier wood blocks to that height. Then, with the wheels off, lower the car until the weight is completely on the rotors on the blocks. (Leave the jack & jackstands in place for safety's sake of course).

With the rear wheels off, you'll have plenty of access to tighten the bolts for the a-arm inner bushings.

That's the way we old shade tree mechanics did it before we got old & lazy & acquired a lift(LOL).

 

One thing about the bushings. My old rubber bushings were REALLY awful looking...all cracked and nasty. But when we got the A arms out and really started trying to press them out, they were in a lot better shape than I thought, even after being baked in the powdercoating oven at 450 degrees! To be honest, they probably didn't even NEED to be replaced, but what the heck, it was only another $120 for new bushings. (Sigh!)

Birdman[/QUOTE]

Birdman,

Very nice job on the photos and write up.

I am waiting for the bushings to arrive, A arms, shocks, and sway bar bushings. My A arm bushings also look awfull, as do two of the drop link bushings. The shocks look like they might come out more easily, so i will try them first - road test. Then try the sway bar bushings - road test. If that doesn't get rid of the noise, then I will do the A arms.

thanks,
chris

 

I've got a question for all those who have replaced their bushings...

Why not remove the polyurethane from the sleeve before welding?

Question #2

Shouldn't they be removed anyways and lubed up with the tube of grease that comes with each bushing. If not, what has eveyone been doing with the grease?

Henry

 

Hi Chris
This is what worked for me -
Max neg camber front and rear before you run out of thread for the nyloc nuts (this varies a little from car to car and can only be increased more than about 1 degree by modifying the U brackets mounting to the chassis by using longer bolts.)
Zero toe
Front Max Castor - the 328 spec (if I recall) is 6 deg neg, which was my reference point for 16" wheels - you can just about achieve that by switching spacers top and bottom.
Realign to ensure all is balanced
Take some pyrometer tests at the track and fine tune from there.
I have been experimenting with a GTS rear roll bar (18mm) and whilst my initial impression was not really positive ( made the car a bit "twitchy") I have become more familiar with it now and am beginning to like it.
Good Luck
John

 

Hey Birdman,

Actually, they come apart pretty easily. I just used a socket to push out the inner metal sleeve and was then able to push the polyurethane out with my thumbs. Once this is done, does anyone know of any reason not to lube up both sides of the poly with the grease?

Henry

 

Actually, I beg to disagree. The Poly bushings are constructed differently than the OEM bushings. The rubber on the OEM bushings is basically bonded to the metal surfaces. When the A-arm travels through it's stroke, the inner metal piece puts torsional force on the rubber and that puts torsional force on the outer shell. This can cause the outer shell to move against the A-arm. Also, this is why the OEM bushings must be tightened with the suspension loaded. If you tighten OEM bushings with the suspension at full droop, when you set the car back down, you're loading torsion on the rubber with the car statically laiden (not good).

However, the Energy Suspension bushings are made in such a way that the metal inner core can rotate freely, without putting torsional loads on the poly or the outer shell. The end result is that there is almost no force that would cause the outer metal shell to move in the "socket" on the A-arm.

IMHO, it is not necessary to weld them to the A-arm OR to tighten them with the suspension loaded. On my 79 GTB, I did this mod and then proceeded to put 20K miles of street use and about 2K miles of track use with no problems whatsoever. i inspected for signs of degredation twice in that time period and saw none.

On the other hand, if you feel the need, it probably doesn't hurt anything if it's done right (i.e. removing the poly from the shell before welding).

YMMV