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Discussion Starter #1
So i ran into a little difficulty installing my max motorsports lower k-member brace tonight. (MMBAK4-1) This is on my '88 LX 5.0. Loosely installed the two bolts on one side and when I moved to the other side, I found both mounting holes to be off about 1/2" - 3/4" or so.

Both pics taken looking towards the front of vehicle with drivers side on left. Spacing on the brace is 20 1/2" and 28 3/8". Does anyone have a stock K-member sitting around that they can measure so i can compare spacing of the bolt holes in that? I'm trying to determine if it's my K-member that is "different" or the brace is off.

My car is an original 1988 v8 car that i've owned since the mid 90's. I have no reason to suspect any accidents prior to my ownership. Nothing else in the car is misaligned and I just installed an MM STB and it fit like a glove.
 

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Discussion Starter #2
UPDATE: Well, after getting some measurements from an individual on another forum, it appears my K-member is bent or possibly was constructed incorrectly.

No signs of damage however, and my car still has all it's original panels with VIN tags.

I was planning on removing the engine this summer and installing a full MM K-member kit, so i'll cancel the brace install and wait until i can remove the engine and k-member and investigate this further.
 

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Interesting!

Waaaaay back in early '96 I installed a K-member brace on my car. I don't remember the brand, but I know I had some other Kenny Brown parts on the car, so it may have been KB. At that point the front end was all stock. I remember I had to enlarge the holes to get it to fit - not 1/2" to 3/4", but I definitely had to do some work. I also remember that I didn't have a Dremel tool - not sure I even knew such a thing existed at that early point in my car modding history - so I did it all with a hand file. Lots of time laying on my back under the car in the garage. :p
 

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I Spent some more time under the car today and can't find any evidence of the car ever being hit. Probably looked around a good 2 hours. Both subframes and pinch welds are perfectly straight. So I tried to mount the brace again.

No dice. Looks like i'm off 1/2" or so. In fact, it looks like the K-member was installed slightly cheated to the pass side on the subframe mounting flanges. Perhaps that is limiting my ability to install this? I'm also still off a good 1/2" or so regardless.

Going to shelf this for the meantime. I am planning on a full MM K-member install this coming summer but wanted to install this brace simply because I had it and it looked like a 10-min install. Not going to kill myself here when i'll probably be removing it after 100 miles to do a full K-member.

The black paint is some POR-15 i applied years ago that apparently i forgot to get the other side with.
 

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I had a similar problem as Patrick with my KB G-load brace. The car was an 86 vert so I figured the older K design and being a vert had a little to do with the issue. IIRC, I had to enlarge some holes and jack the piece into place (may have had added pre-load in the process). But I got it in. Made a noticeable difference to the vert.
 

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Discussion Starter #6
I had some unknown 2-pt brace kicking around that i had previously installed years ago but removed when i did my AOD-to-T5 swap. Ended up putting that back on since it was an easy install as i had drilled the holes years ago.

I sold the MM brace to a buddy. Like i said before, i am planning the full MM K-member later this year so i didn't want to spend too much time trying to get this brace in only to take it out 50 miles later.

Still interesting to see my K-member is somewhat "off" for some reason. I'll investigate further when i remove it from the car.
 

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I'm interested to see what you find out about the K-member. The four point brace is the only other piece I haven't added to my build. Mainly because I don't know whether I'll use long tubes or not. I find it curious one never knows what they will find as far as symptoms of different assemblies or manufacturing tolerance differences.
 

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UPDATE.

It's been a year, but I finally pulled the stock K-member out to install a MM k-member. I never ended up selling the brace, so I still had it and decided to try some test fit.

First off, I don't believe the brace was machined improperly. I mocked it up to the MM k-member and the rear mounting points line up perfectly. So the brace is correct.

My k-member, however, is way off. No signs of damage. I looked over it for a while trying to see if it was bent and I simply cannot tell. It looks undamaged.

However laying the brace on the 4 mounting points, I can see that they are narrower by about 1" than where they need to be.

Here are some measurement points:
Rear inner mounting bolt holes: 27 5/8"
front mount holes: 20 1/4"

Front LCA mount hole center to center is 23.75", so it matches up to what an 88+ v8 k-member should be. But it's running narrow on the rear mount pad holes. I see ZERO evidence of frame rail damage. All my body panels show no evidence of damage, and all my original VIN tags are in place showing my damage free fenders and doors are original to the car. With engine bay stripped I can see the rail runs perfectly straight all the way back, but the rear pad is running narrow. I may need to slot the holes on my MM K-member.

So, not sure what is going on. I have pics but it just shows that with the brace in place, all 4 mounting locations are about 1/2" inboard of where they need to be, and zero evidence of damage.

Anyway...just wanted to update
 

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Discussion Starter #9
The photos. Centered as best I could and then took a pic of all 4 mount locations. Up is front of car

Again, I believe the brace is made correctly, but something is up with my K-member. The rear pads are narrow by about 1/2" compared to my MM K-member. Front mount holes line up fine.
 

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Mike,

Measure the center to center spacing of the holes in the rear nut plates.

Also measure the center to center spacing of the rear slots in the k-member.

On the bottom of the rear mounting pads of the k-member or on the bottom of the k-member right in the middle, will be a year code stamped. What is it? The date in the middle is usually unreadable due to the car being bottomed out against the ground.
 

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Discussion Starter #11
Jack,

On the stock K-member:

Center to center, rear inner nut plate: 27 3/4”
Rear frame rail slotted holes: 32 3/4”

On the actual car, I also measure 27 3/4” for the inner rear nut plate holes.


Date on K-member is 1-26-88
 

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Mike,

Wrong data.

I mean to measure the c-c spacing of the two holes on one of the plates. Also the same thing for the slot spacing on the k-member. The measurements should be between 2" and 2.5".
 

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Discussion Starter #13
Jack,

2” on both.
 

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That's normal. The pre 1983 k-members have a 2.25" bolt pitch for that joint. The outer bolts are in the same position, but the inner bolts are each 0.25" closer to the centerline of the car. I suspect that the change was made for more clearance to the catalytic convertors.

Your k-member is very strange.
 

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Discussion Starter #15
Your k-member is very strange.
Yup.

Normally i'd suggest the car was previously wrecked, but I know this car's history well and I've been searching all over for signs of damage and every crease on it looks factory. With how those rear nut plate tabs mount to the firewall area, there's no way they can move an 1" inward without some sort of evidence. I can't find it.

I'll mock up the MM K-member real quick one of these nights to see how it fits in. I'll toss the 4-pt brace on ebay.
 

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Discussion Starter #16
Just to update and close out this thread.

I took my new MM K-member and ran a test fit. What I found was that the rear mounting perch on the driver's side was about 1/2" inboard of where it should be. I was able to bolt up the 4 main k-member mounting bolts, and the pass side nut plate with each. So it looks like the issue was in my car.

Absolutely no visible indication of a hit in the body structure. I assume what happened (and Jack gave me some offline info) was that at some point prior to me getting the car, it must have taken a hit on the driver's side wheel and bent the K-member. Vin-marked fender shows no damage on the backside. I no longer have any of the original suspension/wheel components to investigate any witness marks or damage.

Anyway, there you go. Factory K-members are strong, but apparently can be bent.
 

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On my 86, I discovered the rear upper PS spring pocket had been deformed so bad that the spring pigtail would not sit flush in the pocket. This caused the PS rear to sit about .5" higher than the DS rear. No other indication of body damage or repair. And I bought the car with very few miles. The only way to get an even ride with conventional springs was to cut the PS iso into a "c" with the mouth where the deformation was, and use an extra iso on the DS. Thereafter, I used MM's adjustable perch LCAs, but still needed the prior iso setup to get the adjusters even. In my case the deformation was apparently factory.
 

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Discussion Starter #18
I can’t conclusively say the defect was factory or a slight hit. I also bought the car are relatively low mileage literally from a 60 year old woman (was an AOD at the time) in immaculate condition, so I’m surprised at the notion of a possible hit.

Still, for it to be a factory defect would mean the k member was also tweaked. I would bet if I found another stock k member and tried to mount it up, it won’t fit.

Either way it doesn’t matter. I’ll make it work.
 
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