Front Suspension - Upper Control Arms - Cutting and position?

Hello everyone,

After checking several build threads and even specific threads about the UCAs, I still find myself not totally clear on this topic, and given that one of the potential solutions involves cutting a part, I want to make sure I got it 100% right before pulling the trigger. And as it is relevant to my question, I do have power steering for my build.

I understand that the UCAs are flipped, meaning the Right Side/Passenger Side UCA has 2 pivot bolts towards the front of the car and the Left Side/Driver Side UCA has only 1 pivot bolt towards the front of the car. However, after playing with the sleeve and jam nuts, I can't get the side with only 1 pivot bolt down to 7.375', which seems to indicate I do need to do some cutting. According to my diagram, are these the sections of the UCAs that need to be cut?

Attachment 154023

1. What needs to be cut and by how much? The ends of the sleeves (red boxes) and/or the threads (yellow boxes)?
2. Any best practices to do this? Type of saw, spray WD40 before cutting, etc?

Attachment 154024

Lastly, I also saw mentioned in some threads to add grease or anti-seize inside of the sleeves before putting it back together, but it's not mentioned in the manual. Is this a good idea or not?

Thank you everyone in advance!

Sorry, my manual isnt with me, but I also ran into an issue with adjustment here. Take a close look at the manual before you cut anything if you so choose. The lengths shown are for front and back sides, not necessarily the number of pivot bolts.

What I'm trying to say is if you choose to cut, you will be cutting one UCA on the two bolt side and one on the single bolt side.

The location you marked in your second picture is where I cut mine. I didn't use never-seez when putting it together, but also haven't driven it.

It's not the welded vs un-welded legs. You don't have to cut the link that's on the front (as there mounted on the car), only on the rear link. I cut the round section off both rear links, then assembled, screwing in threaded ends all the way in to determine how much to cut off.

I've made these changes to my MKII. Someone should confirm if it's the same for a MKIV. You want to shorten the REAR adjuster on both sides (not the front/rear you have shown) approx. 1/8" on each end, this will remove most of the round stock just back to the hex. The best way to do this is on a lathe or mill, the Al cuts very easily. The two REAR leg threaded pivot studs are trimmed the same amount (1/8" each). A hack saw and file/grinder to clean up the cut works fine. You should test assemble the adjuster and pivot studs to make sure you can fully shorten the leg without bottoming the studs against each other. Anti-seize on the threaded studs and adjusters on final assembly is a good idea. Good luck. Scott

These answers are great because they are addressing something I was confused by. I understood the diagram on the manual that for either UCA, the 8.23' dimension is always for the side with 2 pivot bolts, and since they are placed in an inverted position between Passenger Side and Driver Side, I would cut the sleeve closest to the front for the Driver Side UCA and the sleeve furthest from the front on the passenger side (like I drew on my photo). Is that not the case? Is the dimension 8.23' always on the side facing the front? It's a bit hard to explain this without pointing directly to the part, but I'm basically referring to my first picture in my first post.

The 8.23" dimension is for the front leg. You want to shorten the rear leg on both sides. So in your picture, you want to cut the rear adjuster on the left UCA vs the front leg you have shown in red.

I found this thread that will probably help. Scott

https://thefactoryfiveforum.com/show...-Alignment-Mk4

Let's back up a second. The UCAs end up being installed so on one side of the car the welded piece is to the front. On the other side of the car the welded piece is to the rear. The way you have them laid out in your first pic (forget your labels for now, just look at the basic pic) is correct. Or you could turn the picture around 180 deg and install them that way. It doesn't matter. The dimensions that FFR gives are an approximation to get the car somewhat close to OK w/o actually doing an alignment. They do this because people are usually installing the suspension many months (years?) before it will be driven. Honestly I would forget those dimensions. I have helped align several MkIVs and you can usually get about +6.5 deg caster with -1/2deg camber w/ the stock parts. This isn't terrible but many of us prefer the feel provided by +8deg or so caster. (A quick aside; caster is the angle of the spindle when looked at from the side of the car. More caster means the spindle is leaned backward at the top more) So to get that extra caster the sleeve on the rear of each side of the car needs to be shortened. I usually machine away the round section on each end. It is simply an easy guideline to machine by so no need to keep measuring as metal is removed. BTW I am happy to do this for anyone who needs it on my lathe. Email me at craigstuard at comcast dot net with FFR sleeve as the subject so I don't delete it because I don't recognize the sender name. I don't charge to do this but ask you to stick a $10 bill in your box to cover the return shipping.

This was the thread I used and found to clarify a lot of my questions

https://thefactoryfiveforum.com/show...-Alignment-Mk4

IIRC, I had to reassemble my UCAs out of the box and flip some pieces around. you want the grease fittings pointing up and the ball joint fittings ultimately pointing out and not in. As CraigS mentioned, the control arms are the same and not mirror images, so you'll have the welded portion of one of the arms at the front of the car and it'll be towards the rear on the other side. For power steering, to get more caster, the rear sleeve and bolts will need to be trimmed to get close to the recommended numbers. CraigS's offer to machine them for you is very generous and I would have considered it if I didn't have a manual rack. Also make sure to remove the anticorrosive coating on the threads of your ball joints to get them to easily thread into to control arms.

Thanks for the responses! If I'm understanding everything correctly:

It is not like this first image...
Attachment 154081

But like this second image...
Attachment 154082

Of course, with the ball joint mount in the direction that makes the ball joints point outwards instead of inwards, and with the grease fittings pointing up, not down.

Attachment 154083

Then take 1/8'' from the adjuster sleeves as well as from the threaded ends.

Is this summary correct?

Yup, I think you've got it. Scott

Exactly.

Quote:

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Originally Posted by CraigS

Let's back up a second. The UCAs end up being installed so on one side of the car the welded piece is to the front. On the other side of the car the welded piece is to the rear. The way you have them laid out in your first pic (forget your labels for now, just look at the basic pic) is correct. Or you could turn the picture around 180 deg and install them that way. It doesn't matter. The dimensions that FFR gives are an approximation to get the car somewhat close to OK w/o actually doing an alignment. They do this because people are usually installing the suspension many months (years?) before it will be driven. Honestly I would forget those dimensions. I have helped align several MkIVs and you can usually get about +6.5 deg caster with -1/2deg camber w/ the stock parts. This isn't terrible but many of us prefer the feel provided by +8deg or so caster. (A quick aside; caster is the angle of the spindle when looked at from the side of the car. More caster means the spindle is leaned backward at the top more) So to get that extra caster the sleeve on the rear of each side of the car needs to be shortened. I usually machine away the round section on each end. It is simply an easy guideline to machine by so no need to keep measuring as metal is removed. BTW I am happy to do this for anyone who needs it on my lathe. Email me at craigstuard at comcast dot net with FFR sleeve as the subject so I don't delete it because I don't recognize the sender name. I don't charge to do this but ask you to stick a $10 bill in your box to cover the return shipping.

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Craig, I have watched this "thread shortening" thread, and reviewed the referenced thread, and it occurs to me that the assembly procedure must not point out the end-in-mind of achieving larger caster numbers.
The bearing housing flip (R-L) confused me until the geek's end view revealed that these bearing housings are different from my QA1 bearing housings. The QA1 ball joints and threads are perpendicular to the lateral plane so flipping is not required, my fixed studs are both forward. If I did flip the QA1s I would have altered caster and wheelbase R-L. Some of these attached photos suggests flipping creates a caster (wheelbase) disparity which further confuses. A bit more manufacture tooling would provide aesthetic symmetry.
jim

Quote:

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Originally Posted by elspanishgeek

Thanks for the responses! If I'm understanding everything correctly:

It is not like this first image...
Attachment 154081

But like this second image...
Attachment 154082

Of course, with the ball joint mount in the direction that makes the ball joints point outwards instead of inwards, and with the grease fittings pointing up, not down.

Attachment 154083

Then take 1/8'' from the adjuster sleeves as well as from the threaded ends.

Is this summary correct?

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you should email those to davel@factoryfive.com to update the manual - great pics!

Jim you are correct. I am not sure of the current supplier to FFR but SPC has nearly identical parts. The UCAs are off the shelf parts. The ball joint plates are available in either flat or angled configuration. FFR chooses to use the angle version. I think that welding one of the studs to the plate is done, 1- to simplify things by getting rid of one bolt and nut and 2- it also prevents a situation where friction of the ball joint might overcome the tightness of the small bolts/nuts and the plate gets rotated by steering the car. Certainly they could build them so the welded stud is in the same position on both sides of the car but then they would need another part number for another ball joint plate.
https://www.spcalignment.com/images/...156/index.html
I use this catalog but order through Summit. I have heard though that if you need a complete arm it is better to call SPC and order from them because a complete arm will be less expensive than the parts. For an FFR you want;
93400 shaft
92025 pivots (you could use the 94014 but I really like how the grease disperses thru the channels in the 92025s)
92002 plate
sleeves that I don't remember the lengths of but note that steel sleeves can be had that are 1/4 inch shorter. Also in the past some builders needed slightly longer sleeves for the front.
94002 ball joints. Note that the industry # for these is K772 which often shows up in other catalogs.
92005 and 92014 studs.
BTW this catalog is worth looking through for other projects as they have some really nice parts especially for the purpose of making non-adjustable OE suspensions adjustable.

Craig, I learned of the configuration years ago from my local short track racing shop. They carry all the parts "a la carte" and I bought whatever was close and cut to fit.
The welded stud stabilizes the ball joint housing.
The angle/housing would work better for me with my fabricated uprights. My perpendicular ball joint housings work best with flat angle UCA, not quite my case, but the camber gain is good.

Ordering through a local shop is an exercise in patience but Summit has not been timely either. SS Vibrant exhaust bends are back-ordered, yeah, China and the West Coast port.
jim

Quote:

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Originally Posted by J R Jones

Craig, I learned of the configuration years ago from my local short track racing shop. They carry all the parts "a la carte" and I bought whatever was close and cut to fit.
The welded stud stabilizes the ball joint housing.
The angle/housing would work better for me with my fabricated uprights. My perpendicular ball joint housings work best with flat angle UCA, not quite my case, but the camber gain is good.

Ordering through a local shop is an exercise in patience but Summit has not been timely either. SS Vibrant exhaust bends are back-ordered, yeah, China and the West Coast port.
jim

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Craig, That indeed is a great catalog resource. Finding that part without your part number on Summit is difficult. I see that plate is 10 degree, I may get two. I hope they fit my QA1 ball joints.
jim

Quote:

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Originally Posted by toadster

you should email those to davel@factoryfive.com to update the manual - great pics!

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I totally agree. I had the same confusion and these pics / instructions are great.

Once you find one of the SPC parts at Summit you see that the Summit # is something like SPC92025. They add a prefix or suffix so once you have that it is easier to find any others. As long as your ball joint is a K772 type it should fit. I used this one
https://www.summitracing.com/parts/qa1-1210-105
BTW I have the adjuster tool that I would be happy to mail to you if you don't have one.

Craig, I use the same ball joint and I bought the wrench to tighten it. I had to ream the upright (metric) tapers to SAE 7 degree with a Speedway reamer. Tricky without a mill.

On the off topic of Summit and part numbers:
I am building headers for a Blueprint LS3 going into my buddy's 98 C5 Corvette. 2" primaries, 3" collectors. All SS Summit parts.
The 4 into 1 slip-fit collector part number is XFO-CL4S-200-300 from X-Force. The parts arrived 2.0 primary 3.5 collector.
I called Summit and sent them back and received the same thing in return.

I wrote X-Force and they told me they do not make a 2.0 primary, 3.0 collector. Their (and Summit's) part numbers are for a 2.0 primary, 3.5 collector!??!
I cut the second set and made them work. They are from China and not cheap.
jim

Attachment 154182

Does anyone know if the same upper control arm modification needs to be done on the mk5? I noticed on my mk5 that the mount points for the upper control arm are different, but the control arms appear to be the same. I would rather modify things now while it is easier to do.

Quote:

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Originally Posted by Reno

Does anyone know if the same upper control arm modification needs to be done on the mk5? I noticed on my mk5 that the mount points for the upper control arm are different, but the control arms appear to be the same. I would rather modify things now while it is easier to do.

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I didn't read this entire thread (5+ years old) but just to be sure -- the "mod" typically done to the UCA's is to make sure there's enough adjustment to obtain the added caster power steering allows. The Mk5 (I'm building one too) has the same front suspension as my Gen 3 Coupe. It has power steering and did not require trimming to obtain full +8 degrees caster. My Mk5 build also has power steering and I didn't trim anything during assembly. I haven't aligned it yet so can't say yet whether that was the right choice. But frankly I don't think they're that hard to take apart later and trim if needed. But bottom line, just to be clear, the trimming is only required for power steering builds and may/may not be required.

Thanks Edward, I am also using power steering. I think I will wait and see how it goes. As you said it really wouldn't be too difficult to take this out later. Good luck with your build!