Driveshaft caps hitting.

[Johnc1]

After inspecting the power train I noticed the drive shaft caps had been hitting the shaft face. How I’m not sure. The rear-end is solid and all the links are tight. But the angle on the transmission is 0 and the pinion is at 4 degrees up. The drive shaft fits and turns good with no binding at all. I’m out of adjustment on the upper links. So if I need to go more to get the pinion down I am out of luck. Any suggestions would be appreciated. Not sure that what cause it.17525

[Dan Babb]

Sounds like you need to adjust the trans and pinion angles. I believe they need to be opposite each other. So if pinion is down 1degree, angle at the trans is up 1 degree.

Info here
http://www.carcraft.com/howto/91758/

[frankeeski]

Pinion need to be angled down, not up.

[Jeff Kleiner]

Pinion need to be angled down, not up.

Yep, but remember when we speak of pinion angle we are referring to the pinion shaft relative to the transmission's output shaft. When determining pinion angle you can leave the driveshaft on the workbench, and in fact if you follow my method described below it will be easier if you do just that

Don't get caught up or confused on any thoughts of horizontal. Think of it this way; when looking at the car from the side if you were to project one line from the transmission output forward and another line from the pinion shaft forward with your pinion angle at zero they would be parallel. If you put any angle to the pinion the two lines are not parallel and would get farther apart as they go forward. If the pinion were to be angled UP (relative to the trans) it's line would be above the output line; if it were angled DOWN the pinion line would be below. Below is what we're after. Clear as mud?

My method for ease of measurement:
Set ride height then put the car on jackstands so that the axle is loaded. We don't care if the frame is dead nuts level; we're only going to look at the difference between output shaft & pinion. We know that the crankshaft and trans output shaft are parallel therefore the face of the damper/ crank pulley is perpendicular to the output. We also know that the pinion flange face is perpendicular to the pinion. See where I'm heading? For me it is easier to get a good measurement with the magnetic angle finder by reading vertically on the crank pulley/ damper and pinion flange rather than trying to work with the horizontal shafts themselves. Once you can see the two angles you can then calculate the difference. Generally with these cars we want the pinion down ~1-2 degrees (once again, meaning the input is pointing down in relation to the transmission output shaft). Reason being is so that when the axle tries to rotate it's input upward under accelleration the pinion angle becomes less. This rotation is especially more pronounced on a 4 link car using the soft rubber bushings in OEM Mustang arms vs. a 4 link car with poly bushings or a 3 link with polys in the lowers and the solid upper link.

Adjustment of 3 link or a 4 link with aftermarket adjustable uppers is easy; simply alter the length of the upper link. If your pinion is pointing up that would mean shortening the link(s). If you are out of adjustment or do not have the ability to change the length of the upper link the rear of the trans can be raised to accomplish the same.

Good luck,
Jeff

[CraigS]

Pinion angle is one element of the equation. The other is axle travel relative to the trans. At normal ride height the driveshaft should have a slight down angle to the rear. AT the pinion end it should be between 1/4 and 1/2 inch lower than at the trans end. This will allow for slightly more up travel of the axle to absorb bumps. The easiest way to adjust this angle is to adjust the ride height. But you may not like the resulting ride height. I have my trans shimmed up about 3/8 inch so I can run the car at the height I want and still have the drive shaft angle I need. So, get the pinion angle adjusted first using Jeff's method, and then check the driveshaft angle.

[Johnc1]

Thanks to you all for the help. I’m going to go back and redo the measurements. Now that I think I have a clearer picture of how to do that.

[Johnc1]

Hi Craig can you expand on the ride height and how you set it?

[Dan Babb]

Confirm in the manual, but I think the ride height is around 4".

You measure that from the bottom of the large round frame tubes to the ground. Measure at the front & rear. To adjust it...jack up the car so the wheels are hanging in the air. That allows you to turn the spring adjuster on the coil-over shocks (or whatever rear spring setup you have).

Depending on your springs and wheel setup, you may need more than 4". You'll find out when you're driving. If the wheels hit the body, you need more.

[CraigS]

John, as Dan says you measure from the bottom of the main frame tubes. One thing to add is that you should always make sure the left and the right are the same. Since most of us don't do the corner weight thing the best we can do is make sure it is mechanically equal left to right. I do that by counting the number of threads showing beyond the adjusting collars on the coilovers. Make sure left equals right (and this goes for the fronts too). Front will be different from back but left should always equal right at both ends. Assuming nothing hits going over a big bump, height is somewhat subjective depending on wheels, tires, and personal visual preference. Most of us are between 4 and 4.5 inches in the rear.

[Bob Cowan]

John, as Dan says you measure from the bottom of the main frame tubes. One thing to add is that you should always make sure the left and the right are the same.

I would disagree with that. It didn't work out that way with my car. Here's my suggestion:

- Place the appropriate load in the appropriate positions.

- Raise the front and rear of the car, so the tires are off the ground. Turn the spring collars down until the are just touching the tops of the springs.

- Set the car down, and settle the suspension. Measure ride height.

- Adjust both sides exactly the same to get the ride height pretty close to where you want it. They will NOT be exactly the same.

- Do the same until front and rear ride height are where you want them to be.

After I set my ride height this way, I put the car on the scales. The weight balance was so close to perfect, I didn't touch it. I figured the only thing I could do was mess it up.


As for adjusting the pinion angle, there is one key point that is often mis-understood. You are comparing the pinion angle to the power angle, and NOT the horizon. This is the key point that you need to be able to visualize before you start.

[Johnc1]

The protractor on the engine dampener shows 1.5 degrees down for the output shaft. On the pinion flange it shows 3.6 degrees up. That is jack stands on the axles and weighted. The upper links have been adjusted as short as they will go.
I put new caps on the drive shaft and went for a test drive. It runs smooth and no vibration. No signs of hitting.
The figures do not add up. And I do not know what did the damage to the old caps. Do you think under hard accel that it can get enough rap-up on the rear-end housing to course the drive shaft damage.
Again thank u all for the help.

[Bob Cowan]

The protractor on the engine dampener shows 1.5 degrees down for the output shaft. On the pinion flange it shows 3.6 degrees up.

That gives you about +2.5* pinion angle. What you want is about -1 to -1.5*. The thinking is that with a good suspension set up, when you mash the throttle you'll gain about +1 to +1.5* of pinion angle, getting you pretty close to 0*.

You now have about +2.5*. When you mash the throttle, you'll have +3.5 to +4*. That will put a lot of strain on your U-joints, and you're risking a catastrophic failure.

[Johnc1]

I hear you Bob. I have room on the bottom link brackets to changes the location of the mounting point moving the bottom of axle housing back. That would bring the pinion angle down or I can add to the lower links making them longer.
The upper links and mounts will be hard to change unless I can find off set bushings.
I believe the rear end may have been a SSBC setup. I also could drop the output location there is about a 1/4 inch to play with.

[Dan Babb]

The protractor on the engine dampener shows 1.5 degrees down for the output shaft. On the pinion flange it shows 3.6 degrees up.

When you measured the front, did you have the car level?

To get the most accurate reading, I think you'd need the frame tubes level. So if you have the rear on jackstands, then you need the front lifted up enough so your round tubes are at 0 degrees.

Then take your angle readings on the front damper and the rear pinion.

[Johnc1]

When you measured the front, did you have the car level?

To get the most accurate reading, I think you'd need the frame tubes level. So if you have the rear on jackstands, then you need the front lifted up enough so your round tubes are at 0 degrees.

Then take your angle readings on the front damper and the rear pinion.

Yes it was level, but I would think that it is the difference between the two that we would be looking for. Am I thinking wrong? If I jacked the car so the dampener reads 0 then the pinion would still be +2.5 degrees. The two should move together as long as the weight is on the axle. So the pinion needs to move down looking for the two to match. If I am look at this right the output being -1.5 then the pinion needs to be +1.5 or better 0. To do this I need to move the top of the axle housing in or the bottom out.

[Jeff Kleiner]

Yes it was level, but I would think that it is the difference between the two that we would be looking for. Am I thinking wrong?

You are correct. As Bob & I both stated earlier you can disregard level or horizontal when measuring for pinion angle. It doesn't matter if you stand the car on it's nose, in the end what matters is the difference between the output shaft and pinion shaft angles.

Jeff

[Johnc1]

I am going to look at how much I need to move the mounting point on the bottom of the axle housing. I do not believe it would be much. Is there a preferred way? It looks like I can weld the holes closed add some extension and move the mounting holes forward. We are talking about the bracket that bolts to the bottom of the axle housing. It has the bottom drag links connected on the front and the shocks mounted to the back of the bracket.

[Jeff Kleiner]

I'm surmising that this is a 4 link, right? Mustang coil springs or coilovers? I think the root of your problem is the upper control arms, which being adjustable are obviously aftermarket of unknown heritage, not OEM or from FFR. If you start monkeying around with effectively shortening the lower control arms or their mounting point you will end up moving the rear wheels forward in the wheelwells which could end up looking wonky. For me step 1 would be to see if enough change can be made by using different spacers at the trans mount and then step 2 would be different or modified upper control arms.

Jeff

[Dan Babb]

Pictures of the underside of the car are here:
http://dc-classic-cars.ebizautos.com/detail-1967-ford-cobra-factory_5-used-10177564.html

Last pictures shows the rear end. Looks like a 4 link, but also has a panhard setup. Not really a tight enough shot, but it almost looks like the upper arms are adjustable.

[Jeff Kleiner]

Hmmm... That is a 9 inch rear end. 4 link with a panhard bar. Talk about something with a lot of built in bind! Since this is neither FFR or OEM I'm afraid you're going to have to take a step back and do some rework. I'd start by shortening those uppers.

Jeff

[edwardb]

Hmmm... That is a 9 inch rear end. 4 link with a panhard bar. Talk about something with a lot of built in bind! Since this is neither FFR or OEM I'm afraid you're going to have to take a step back and do some rework. I'd start by shortening those uppers. Jeff

Jeff beat me to it... I was looking at the pictures at lunch while at work today, but didn't have time to comment. 9 inch rear, upper links, panhard bar. Obviously have no idea who built it, but quite a combination. Hard to see the coilovers but I think something is there. Also assume without the A-frame under the transmission it's earlier than a Mk3. I would really think about trying to get it back to a more proven FFR setup. The 9 inch is probably OK, but need to decide whether it's a 3-link or 4-link.

[Johnc1]

It is a 4 link with a panhard bar. I have adjusted the upper links as short as they will go. I will pull the wheels on Sunday and take some pictures of the set up. It is not what I would have built myself but it is what I have to work with. I have to say it handles better then you may think. Hole shot is great.
By adjusting the upper links all the way in I have not seen any more damage to the drive shaft caps. But I still have those + 2.5 degrees I want to try and get out. The shocks are adjustable coil-overs mounted to the back of the same bracket the lower link is mounted to.

I believe the car was built in Ohio. Most of the parts are SSBC and Strange. It look like the original builder was looking at drag racing.
If the weather is good tomorrow I plan the take it to a local show in Edenton NC. Easy run, feel things out.

[CraigS]

Not sure what type upper links you have but, if I were going to modify anything, that is where I would do it. That way, later on, the only modified parts are bolt on stuff that are already non-FFRstandard.

[Johnc1]

Hmmm... That is a 9 inch rear end. 4 link with a panhard bar. Talk about something with a lot of built in bind! Since this is neither FFR or OEM I'm afraid you're going to have to take a step back and do some rework. I'd start by shortening those uppers.

Jeff

It is a 4 link with adjustable coil overs and a panhard bar 9 inch. It is set up for hard hole shot but I think they located the upper mounts wrong on the axle housing. So there is not enough adjustment in the upper link. The upper links I believe are Lakewood. I will look closer Sunday.

[Johnc1]

Hi Graig, I would like to bring the links in more but I will have to pull the rear-end and cut the mount off and relocate them. This is doable. Jeff mentioned changing the shims under the transmission tail.

[Johnc1]

I'm surmising that this is a 4 link, right? Mustang coil springs or coilovers? I think the root of your problem is the upper control arms, which being adjustable are obviously aftermarket of unknown heritage, not OEM or from FFR. If you start monkeying around with effectively shortening the lower control arms or their mounting point you will end up moving the rear wheels forward in the wheelwells which could end up looking wonky. For me step 1 would be to see if enough change can be made by using different spacers at the trans mount and then step 2 would be different or modified upper control arms.

Jeff

Jeff if the tail stock output is reading 0 and the pinion is +2.5 am I correct by bring the output to - 2.5?

[Johnc1]

Dose any one recognize this car? It was in South Carolina. I would like to get some history on it. My plans are to do the big mods this winter. Try to ride this summer.

[Johnc1]

After reading all the post here and on other forums it is clear there are a lot of opinions. 3 link, 4 link, 5 link. I will need to kick this around. I even found were triangulation 4 link with a pan hard bar was used.

[edwardb]

After reading all the post here and on other forums it is clear there are a lot of opinions. 3 link, 4 link, 5 link. I will need to kick this around. I even found were triangulation 4 link with a pan hard bar was used.

You're right. Lots of debate on that topic. And throw IRS into the mix too. 4-link was the original donor Mustang setup, and with a lot of aftermarket parts including coilovers, can be made acceptable and is considered good for launches but not as good for track work due to possible binding. 3-link is probably the most common choice, and solves the binding issues of the 4-link. Good for track work. 5-link is a non-FFR setup from Levy Racing that is supposed to be good (I hope so, I'm building a Mk4 with it) but not nearly as common as the others. IRS by all accounts is the most comfortable. Combining the setups, e.g. panhard bar with a 4-link, is pretty unusual. First I've seen it, although I don't have the experience of some other forum members.

[Bob Cowan]

I even found were triangulation 4 link with a pan hard bar was used.

I would not recommend this. The 4 link is a triagulated set up. The upper arms are angled sharply inward to keep the rear centered, and allows it to move straight up and down, with no side to side movement.

A panhard bar is used with something like a 3 link suspension. The three link allows up and down movement, but also allows side to side movement - which is a bad thing. The panhard bar connects one side of the frame with the opposite side of the axle housing to prevent most side to side movement. BUT, because it's a single bar, as it moves through it's range, the end moves in an arc. Which will allow some predictable amount of lateral movement. If you have a 4 link installed, it will bind up. A stock 2005-2009 Mustang has a 3 link with a panhard bar.

A 5 link uses 2 lower bars, and 2 coil over, but eliminates the upper bars that you would have in a 3 link or 4 link. Instead of a panhard bar, it uses a Watts Link. It's a little more complicated, but allows full up and down movement and zero lateral movement. It's extremely efficient.

http://www.pro-touring.com/attachment.php?attachmentid=53044&d=1325041932

[Johnc1]

You're right. Lots of debate on that topic. And throw IRS into the mix too. 4-link was the original donor Mustang setup, and with a lot of aftermarket parts including coilovers, can be made acceptable and is considered good for launches but not as good for track work due to possible binding. 3-link is probably the most common choice, and solves the binding issues of the 4-link. Good for track work. 5-link is a non-FFR setup from Levy Racing that is supposed to be good (I hope so, I'm building a Mk4 with it) but not nearly as common as the others. IRS by all accounts is the most comfortable. Combining the setups, e.g. panhard bar with a 4-link, is pretty unusual. First I've seen it, although I don't have the experience of some other forum members.

Edwardb I do like levy’s 5 link systems. I have seen it in a couple of FFR’s. I may try and go that way this winter. I took the car out today for a 90 mile drive, ran good and rode good. Two things I want to try are. Support the car on the frame take the coil-overs off. Then bring the rear-end up and move it around to see just how much movement it does have with the pan-hard bar connected. Then take the pan-hard off and try it again. Without the pan-hard it should move like a standard triangulated 4 link and not need the pan-hard. If all looks good I will try it without the pan-hard bar.

[Johnc1]

Bob, what do you think their thinking was for installing the pan-hard bar ? I am thinking they may have thought it would help to stop the axle from duck walking or maybe wheel hop.

[Bob Cowan]

A panhard bar has only one function, and that's to control lateral motion of the rear end. It doesn't work as well as a watts link, but it's cheaper, lighter, and easier to build and install.

[Johnc1]

That is what I understand too. I have disconnected the shocks and moving the deferential with and without the panhard bar the movement and the travel are the same. The urethane bushings give a lot of flex to the suspension. With the suspension all the way up and down no binding in the drive shaft also with it chocked up on one side or the other no binding. I thank everyone for helping me work through the thought process. I still plan to look at the 5 link system. I think by doing the adjustment you all recommended has help smooth the system out.
“O” on a lighter note. One of my friends has bought a new Camaro and has been trash talk all week. He got Snake bit yesterday;)17637

[frankeeski]

A 5 link uses 2 lower bars, and 2 coil over, but eliminates the upper bars that you would have in a 3 link or 4 link. Instead of a panhard bar, it uses a Watts Link. It's a little more complicated, but allows full up and down movement and zero lateral movement. It's extremely efficient.

Bob, I would agree with everything with the exception of a 5-link not using upper links. Fact is a 5-link does use an upper link. A picture of the upper link mount is below. For clarification, a five link is the same as a traditional 3-link setup with the difference being the use of a Watts link instead of a panhard bar. The Watts link allows for the rear end assembly to articulate straight up and down rather than in a arch usually incorporated in a panhard bar setup. Levy Racing's setup uses both adjustable lowers and an adjustable upper control arm.
http://i200.photobucket.com/albums/aa78/frankeeski/5-Link/001-2.jpg (http://s200.photobucket.com/user/frankeeski/media/5-Link/001-2.jpg.html)
And here is a picture of the upper link
http://i200.photobucket.com/albums/aa78/frankeeski/5-Link/021-1.jpg (http://s200.photobucket.com/user/frankeeski/media/5-Link/021-1.jpg.html)
Johnc1. Levy's 5 link will not work with the Ford 9" rear end assembly you have. You will need to either pick up an 8.8 rear end or have the 9" you have refitted to accept the Watts link bracket supplied with the 5-link

[Johnc1]

Johnc1. Levy's 5 link will not work with the Ford 9" rear end assembly you have. You will need to either pick up an 8.8 rear end or have the 9" you have refitted to accept the Watts link bracket supplied with the 5-link[/QUOTE]

Thanks for the pics Frank. Modifying the 9 inch is what I would like to do. I need to research the pros and cons.

[Bob Cowan]

Sorry, I meant a to say "A watts link.... ". Obviously a 5 link needs a top link, or there would only be 4 links. :)

A watts link can work with a 3 link, 4 link, or ladder bar (which does not have upper links). Because a watts link does not allow any lateral movement at all, it can be added to a stock 4 link suspension (like GM) to make it more efficient, and not have to worry about it binding up like a panhard bar would. But a 3rd and 4th link are not a required component, as long as you control axle housing roll.

[Johnc1]

The watts setup look like it is worth trying. And have found a couple that are bolt in or say they are.

[acth4347]

So this car already has the Factory Five LCA's and the 3-link setup for/with the panhard bar based on your photo. It seems to me it would be really easy to add the 3rd link banana bracket to the rearend housing, add the 3rd link upper control arm (assuming the mounting point is there) and get rid of the not so useful UCA's. No binding, plenty of adjustment for pinion and a true 3link setup. Going with the watts is still an option but you may find it a lot more work depending how wiring, fuel and brake lines are run. And possibly that box in front of the gas tank. Just my 2cents worth. Bill

[CraigS]

One thing to also think about is that your current setup isn't all that bad. Out of spec but... I haven't ever dealt w/ an FFR w/ a way out of spec driveshaft angle but have dealt w/ some standard cars after an accident repair. The only noticeable effect was a kind of rumble from about 5 mph to about 30 mph on hard acceleration. If you accelerated normally nothing was felt. SO, since your U-joint contact problem is now fixed, you have plenty of time to figure a more permanent upgrade.

[Johnc1]

Acth4347, I need to ask what is a banana bracket? The center bracket for the 3rd link is not there but would not be hard to install.

[Johnc1]

Craig you are right the system so far is working well. No rubbing, binding or vibrations. I showered down through the gears to check for signs. I put marking die on any parts I thought may have a problem, no marks showed up. This has turned into an interesting project.
My plans for the summer are to enjoy the car, ride with the local rod club and go to car shows. Have fun. If I get the chance and have a safe place to do some corner testing I will.
By the time cold wither set in I should know what direction I want to go. I have a lot of other changes I want to do to make this my ride.

[Johnc1]

If any one comes to Nag Head/ Kitty hawk North Carolina give me a PM. I am just up the road. We can do lunch and talk shop.