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-   164 & 168 (1991-1995) (https://www.alfabb.com/bb/forums/164-168-1991-1995/)
-   -   Re-assembling rear suspension (https://www.alfabb.com/bb/forums/164-168-1991-1995/683508-re-assembling-rear-suspension.html)

Rogue Leader 07-22-2019 12:22 PM

Re-assembling rear suspension
 
Ok so I finally (I think) have ALL my parts together. I've now tried to put it together twice, but I want to make sure 100% that I am doing this right.

https://alfa-romeo.7zap.com/ImgsWate...9F2D28A04A.png

Specifically I am asking about the long bolts marked 14 and 16 in this photo.

When I removed them there were various thickness washers in between each part. I have all those washers I removed. As well I have some extras of the thin ones too.

In putting it back together I assumed it would be possible to bottom out the nut on the small amount of threads on the ends of the top bolt. Despite every combination of washers this is just not possible. However of course if I tighten the nut then the suspension arms only move within the range of the deflection of the rubber bushings. This doesn't seem right.

Then of course there are the plastic caps that go on the ends of Bolt #14. If I pop that cap on the end over a thin washer, and snug the nut up I still get movement without deflection, and I can keep the nut attached using red loctite. Is this what is expected? Or should I just leave everything loose a bit till its all in and then tighten down fully and allow deflection to happen?

On the bottom it seems I would be able to bottom the nut out even with washers so it would move freely, or should i do the same on the bottom too?

richardbradford 07-22-2019 02:17 PM

Interesting questions and would love to know the answers. I know the rear nut on the back of the front suspension arms seems to lock the bush so the only flex is in the rubber itself - which seemed odd but have heard of it on other cars. Begs the question of what position the arms should be in when fully tightened? Loaded or unloaded?

Can I ask what grade steel your long bolts are? 8.8 or 10.9? Galvanised?

Rogue Leader 07-22-2019 02:40 PM

Quote:

Originally Posted by richardbradford (Post 8442568)
Interesting questions and would love to know the answers. I know the rear nut on the back of the front suspension arms seems to lock the bush so the only flex is in the rubber itself - which seemed odd but have heard of it on other cars. Begs the question of what position the arms should be in when fully tightened? Loaded or unloaded?

Can I ask what grade steel your long bolts are? 8.8 or 10.9? Galvanised?

The front bushing on the front control arms flex like that as well which I thought was strange but they only go in one possible way so it is what it is. As far as i could tell as well my nearly 30 year old control arms that i removed the bushings were not damaged, so I guess there is enough flex in them. As well my rear bushings while worn were not spinning in their mount or anything so they haven't torn either.

You bring up a good question, should they be loaded up when tightened?

I'll have to check the bolts when I get home to see the grade. The long bolts were not galvanized, but some other bolts were. I wirewheeled all of them to get the crud/rust/whatever off so the galvanization is gone now anyway. I figured since I won't be driving the car in the winter, a regular diet of silicone spray on all bolts will keep them nice.

Michael Smith 07-22-2019 02:57 PM

Page 21-25 of the 1991 ARDONA shop manual shows three spacers denoted "a" "b" and "c" to be included on those long bolts.

Spacer "a" fits between the inboard ends of each control arm and the subframe, for spacer "a" there are two for each bolt. These are number 17 on your diagram.

Spacer "b" fits between the forward control arm and the strut mounting hole and spacer "c" fits between the aft (adjustable) control arm and the strut mounting hole. Spacer "b" is numbered 17 also on your diagram and spacer "c" is numbered 12.

These spacers should prevent the bolts from bottoming out and jamming the bushes as far as I can see.

Rogue Leader 07-22-2019 07:23 PM

Quote:

Originally Posted by Michael Smith (Post 8442588)
Page 21-25 of the 1991 ARDONA shop manual shows three spacers denoted "a" "b" and "c" to be included on those long bolts.

Spacer "a" fits between the inboard ends of each control arm and the subframe, for spacer "a" there are two for each bolt. These are number 17 on your diagram.

Spacer "b" fits between the forward control arm and the strut mounting hole and spacer "c" fits between the aft (adjustable) control arm and the strut mounting hole. Spacer "b" is numbered 17 also on your diagram and spacer "c" is numbered 12.

These spacers should prevent the bolts from bottoming out and jamming the bushes as far as I can see.

Even if I install thin washers in each position, putting the nut on locks the whole deal solidly together. The only way to not do it is to use the plastic cap over the end as a spacer of sorts and snug the nut to that. However that seems flimsy, but maybe thats the way. Someone here has done this before right?

pinino 07-22-2019 08:03 PM

Quote:

Originally Posted by Rogue Leader (Post 8442578)
...

You bring up a good question, should they be loaded up when tightened?

ALWAYS (at road height), and be sure to torque bolts to specs in manual.

Michael Smith 07-22-2019 08:48 PM

Quote:

Originally Posted by pinino (Post 8442740)
ALWAYS (at road height), and be sure to torque bolts to specs in manual.

The shop manual assumes the control arms are disassembled and reassembled together with the subframe crossmember while it is all out of the car. No mention is made about loading the springs before torquing up the bolts.

Does this thread help?

https://www.alfabb.com/bb/forums/164...1991-164l.html

Note the silvery coloured spacers between the control arm and the strut bracket. Thicker spacer goes to the rear.

pinino 07-22-2019 09:11 PM

Sorry, the proper way set up suspensions is to torque at road height. At road height your bush, now semi-rigid after torquing, can swing either direction without tearing.

Alfissimo Int. 07-22-2019 09:21 PM

Quote:

Originally Posted by pinino (Post 8442762)
Sorry, the proper way set up suspensions is to torque at road height. At road height your bush, now semi-rigid after torquing, can swing either direction without tearing.

Yup. If not done this way, you will wear out bushings much quicker placing unnecessary torque on the bushings. If they are tightened either up on a jack or off the car they they will not be set in level driving position which is basically set at 0.

This is the right way to do it.

richardbradford 07-23-2019 03:35 AM

Quote:

Originally Posted by Michael Smith (Post 8442588)
Page 21-25 of the 1991 ARDONA shop manual shows three spacers denoted "a" "b" and "c" to be included on those long bolts.

Spacer "a" fits between the inboard ends of each control arm and the subframe, for spacer "a" there are two for each bolt. These are number 17 on your diagram.

Spacer "b" fits between the forward control arm and the strut mounting hole and spacer "c" fits between the aft (adjustable) control arm and the strut mounting hole. Spacer "b" is numbered 17 also on your diagram and spacer "c" is numbered 12.

These spacers should prevent the bolts from bottoming out and jamming the bushes as far as I can see.

From memory, the number 17 spacers are the thick ones.

Michael Smith 07-23-2019 05:43 AM

Quote:

Originally Posted by pinino (Post 8442762)
Sorry, the proper way set up suspensions is to torque at road height. At road height your bush, now semi-rigid after torquing, can swing either direction without tearing.

How does a rubber bushing become semi rigid? The bolt passes through the hole in the bushing. Isn't the bushing hole protected by a steel sleeve anyway?

https://alfissimo.com/suspension-rea...g-chassis.html

https://alfissimo.com/home/1264-rear...d-bushing.html

There's nothing to cause the bushing to bind on that bolt which is the only mechanical connection between the inside of the bushing and the outside. Technically, the outside of the bushing only sticks because of the press fit. The bolt isn't driven through the inner steel sleeve so there's no way it makes a difference what position the suspension arm is in when that bolt is tightened.

pinino 07-23-2019 06:46 AM

As you know the standard rubber bushing has an inner and outer metal sleeve with the rubber vulcanized to the sleeves. In the case of a basic control unit (wishbone), the outer sleeve is pressed into the wishbone, making that part rigid; when you tighten the bolt, ca 45 foot pounds, it's the inner sleeve that becomes rigid to the body part. The only flexing of the component is via the rubber itself, a few degrees in one direction, a few degrees in the other direction. Thus if you were to tighten the bolt with suspension parts hanging, when you lower the car, all the flex on the poor rubber is in one direction. On the other hand tightening (properly) at road level, which represents the average height of the car, this is the 0 stress position of the rubber. So as Jason pointed out, doing it the wrong way leads to premature failure of the rubber bushing (especially when you are reassembling the suspension without the bushing renewed). On a super light car like a Lotus, tightening in a jacked position will actually change the ride height of the car when you lower it, not to mention making the suspension quirky, as the rubber of the bushes themselves create unequal resistance to the suspension's movement.

I think that this thread shows, that no matter how experienced a mechanic you are, when working an a component that is unfamiliar to you, you need to carefully examine and catalog the parts as you remove them so you can reassemble them in the right order. There are lots of situations where shims are used to compensate for irregularities in the build; surprise surprise, not all 164s are the same. Something as simple as the AC compressor bracket is a case in point, where a shim might be added on one car at the factory to help align the serpentine belt, a shim here, a shim there, basta. Next car, please, oh, no shims needed, basta.

Rogue Leader 07-23-2019 06:53 AM

Ok so let me see if I get this straight:

Assemble to rear cradle without torquing bolts so the parts can move.

Install all parts, leaving bolts loose as well.

Get car on ground to level driving height.

Torque all bolts which means the bushings WILL be deflecting just like the ones in the front A arms, but that deflection of rubber is ok (this was my main question as that did not seem right).

Do i have it right? if so, anyone know the torque values?

Michael Smith 07-23-2019 07:18 AM

How does the inner steel sleeve bind on the mounting bolt?

The shop manual specifies moly grease on the rear mount for the lower control arm. That indicates that the mounting stud (the rear mount comes with the double ended threaded "bolt" already inserted into the bushing) rotates within the clamping bracket. The bush remains unloaded from a torque perspective.

There is no way the rubber in these bushes can become locked in a particular orientation to suspension movement. That's a lot of rotation to accommodate.

Plus if you substitute polyurethane bushings these need to be greased on the outside where they adjoin the steel sleeve or they squeak.

I say this is one of those mechanics myths.

pinino 07-23-2019 10:42 AM

2 Attachment(s)
Quote:

Originally Posted by Michael Smith (Post 8442918)
How does the inner steel sleeve bind on the mounting bolt?

Mechanic's myth?, oh please.

Well, let's start with bolt #16. This bolt along with two thick washers cinch against the inner steel sleeve of the bushing of the link #2, then the other side of the steel sleeve of the bushing is squashed against the strut bracket with another thick washer in between, metal against metal. Follow the bolt through the strut bracket and the same occurs on the other end. The bolt kills two birds with one stone. When you torque this bolt to 45 ft lbs, it locks both bushings (inner sleeves) from turning. The movement of the links is entirely due to the flex in the rubber, the bushing itself does not rotate. If anything is greased here it would be the the bolt and the nut, as it is very prone to getting oxidized. (I've spend up to two hours removing the lower bolt and the car was not even rusty) I can't explain how polyurethane aftermarket bushings work, I personally prefer the original design.

Tightening the suspension bolts on the Lotus 7, it's also crucial to do this at ride level; just like the Alfa, the flex in the links is due to the flex of the rubber, inner and outer sleeves are fixed.

How much flexing in degrees? Hard to say, and it depends on the length of the links, maybe 2 in each direction.


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