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Making Bumpstops and 315s Work

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Old Mar 5, 2016 | 08:21 PM
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Default Making Bumpstops and 315s Work

I know there are plenty of threads where people have done the BFH mod to fit 315s. I haven't had to do much, but unfortunately when my car is on a lift, the insides of the rear wheels get hung up on the bumpstops. I've seen that most people just cut them out, but I think Pennsylvania State Inspection requires them to be there and functional.

Anyone have ideas on how to eliminate this, yet still keep the bumpstops? I'm not getting rid of the 315s.

(Sorry if this isn't the right section. Seems like bodywork to me.)
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Old Mar 5, 2016 | 08:46 PM
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If you lift from the axle it won't do that
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Old Mar 6, 2016 | 07:20 AM
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Offset a little biased inside? Spacer help?

Unfortunately only lifting from the axle isn't an option. Lifts will cause the same problem.

Look up Rampant....he did it right.

https://ls1tech.com/forums/wheels-ti...stop-tabs.html
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Old Mar 6, 2016 | 08:01 AM
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Originally Posted by OVRKILL
Offset a little biased inside? Spacer help?

Unfortunately only lifting from the axle isn't an option. Lifts will cause the same problem.

Look up Rampant....he did it right.

https://ls1tech.com/forums/wheels-ti...stop-tabs.html
Exactly what I was thinking about doing. Wanted to move them in a little bit, but I wasn't sure it could be done!

I mainly don't want to scrape up my wheels. They look new on the inside and out. They actually sit flush with the fender, and stick out a tiny bit on the driver's side. I'll probably get an adjustable PHB and see if centering up the rear helps at all. It seems to want to catch on the passenger side of the car. If that doesn't provide clearance, I'll be finding someone with a welder who can set them in farther like Rampant did.
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Old Mar 9, 2016 | 10:01 PM
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You can move the bumpstops inward a bit. I machined up some relocation brackets that moved them inward and down since the torque arm mount was banging the tunnel and put a hole in it. New strange double adjustable shocks also helped. I will look for the pics tonight and post them up. It may not work for you. I am running 275/65/15, but moved my rims inward 1" to eliminate crap getting thrown in the quarters.






Last edited by BlackDuk98; Mar 9, 2016 at 10:11 PM.
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Old Mar 10, 2016 | 02:58 PM
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I've seen a thread here where the person installed the bumpstops on the flat part of the rear end facing upwards. I've been running 315's for about 8 months without bumpstops and I can tell you that my tires will bottom out on my rolled fenders before the rear end hits the frame.
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Old Mar 10, 2016 | 08:41 PM
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That looks really clean BlackDuk. I like that a lot.

xny 1989, I was thinking about that too. Figured something would work mounted on the axle facing up. I really need to roll my fenders too before they cut up my nice tires.
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Old Mar 10, 2016 | 10:03 PM
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I will look up a pic, but have any of you looked into a single center bumpstop that stops on the pumpkin? I cannot remember what car was like that. I haven't been under my car yet this year to look if that is an option, but I think that you could make a drop down bracket and mount it.

I think that 90's Blazers had long bump stops, maybe make a plate and mount them in your coil springs like some off-road trucks:



Last edited by BlackDuk98; Mar 10, 2016 at 10:11 PM.
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Old Mar 14, 2016 | 06:21 PM
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Originally Posted by BlackDuk98
I will look up a pic, but have any of you looked into a single center bumpstop that stops on the pumpkin? I cannot remember what car was like that. I haven't been under my car yet this year to look if that is an option, but I think that you could make a drop down bracket and mount it.
That won't work. What happens when you hit a bump with just one side of the car? That side of the axle is going to go up while the other side goes down. Normally the side that hit the bump would simply hit the bumpstop on that side, but if there is nothing there then the tire will hit the fender instead while the center mounted bumpstop for the pumpkin won't be touched at all.
Something like this would be more ideal:
https://ls1tech.com/forums/suspensio...-bumpstop.html
Although I still prefer to have the stock bumpstops and just jack the rear of the car up by the pumpkin...
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Old Mar 14, 2016 | 06:34 PM
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Yeah, I get what you mean. I have an anti roll bar bolted to the bottom of the car and welded to the rear end, so I don't really worry about the body rolling from side to side.

What you are showing in that link looks just like the last pic that I posted, I think that would work nicely. I also prefer them in stock locations, or moved inward a bit like mine which is basically the same deal. I will be changing mine up though, my rear is already narrowed 3" per side, and I will be mini tubbing it, but I will have bump stops for sure.
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Old Mar 16, 2016 | 01:05 PM
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To the OP, are you having issues with the axle hitting the frame? I've never heard of a vehicle inspection where they check the factory bump stops...
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Old Mar 16, 2016 | 05:23 PM
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I removed my bump stops completely 14 years ago....I've never had my rear end hit anywhere or the tires rub anything.

Why are there issues with this....bad roads????

.
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Old Mar 16, 2016 | 06:35 PM
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Originally Posted by LS6427
I removed my bump stops completely 14 years ago....I've never had my rear end hit anywhere or the tires rub anything.

Why are there issues with this....bad roads????

.
Seriously?
Your sig says you have 315s in the rear, is that correct?
Do you have your fenders rolled?
I semi-rolled my rear fenders (did not want to roll them flat for fear of paint cracking and losing structural rigidity in the fender, Ive heard they can get wavy if you get to aggressive) and still have to run bumpstops (trimmed down a little) or my tires will hit the fenders. Before I rolled them my tires would make contact with the fenders on big bumps or dips.
Here are clearance pics of after I rolled the fenders, with my shocks and springs removed so the car is just sitting on the rear bumpstops. Then take into consideration that is NOT technically fully compressed because the stops will compress more under a hard hit, this is just static weight of the car. I couldn't fit my pinky finger between the fender and the tire.
EDIT: Also as a note my car has a fays2 watts link, so the axle is sitting even on both sides, no rubbing side-to-side like with a PHB.
Attached Thumbnails Making Bumpstops and 315s Work-fender1.jpg   Making Bumpstops and 315s Work-fender2.jpg   Making Bumpstops and 315s Work-fender3.jpg  
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Old Mar 16, 2016 | 09:04 PM
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Originally Posted by 1999nbmZ
To the OP, are you having issues with the axle hitting the frame? I've never heard of a vehicle inspection where they check the factory bump stops...
No, no issues here. And when I had my old K20 Silverado in for inspection, they weren't going to pass it unless they got a new bump stop for it (missing a bump stop). Maybe just a truck thing,but I don't want to take any risks.

Originally Posted by LS6427
I removed my bump stops completely 14 years ago....I've never had my rear end hit anywhere or the tires rub anything.

Why are there issues with this....bad roads????

.
I do have bad roads where I live (PA). Bottomed out the car once on a dip in the highway, but I would've been fine if I wasn't racing lol.

I just don't want to take any chances. Obviously they were integrated into the design of the car for a reason.
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Old Mar 17, 2016 | 04:57 AM
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Originally Posted by JD_AMG
Seriously?
Your sig says you have 315s in the rear, is that correct?
Do you have your fenders rolled?
I semi-rolled my rear fenders (did not want to roll them flat for fear of paint cracking and losing structural rigidity in the fender, Ive heard they can get wavy if you get to aggressive) and still have to run bumpstops (trimmed down a little) or my tires will hit the fenders. Before I rolled them my tires would make contact with the fenders on big bumps or dips.
Here are clearance pics of after I rolled the fenders, with my shocks and springs removed so the car is just sitting on the rear bumpstops. Then take into consideration that is NOT technically fully compressed because the stops will compress more under a hard hit, this is just static weight of the car. I couldn't fit my pinky finger between the fender and the tire.
EDIT: Also as a note my car has a fays2 watts link, so the axle is sitting even on both sides, no rubbing side-to-side like with a PHB.
Yes, I have 315's...since 2002. And I'mn lowered on G2 Super Springs quite a bit.
Did not roll my fenders.

I may have bottomed out before or maybe the axle hit the car, but man I never feel or hear it. Might have happened. Theres no visible contact spots anywhere.

Maybe I should go to the junkyard and get some bumpstops and cut them down some and put them back in....just in case....lol.

.
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Old Mar 17, 2016 | 06:24 PM
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Originally Posted by BlackDuk98
I need to do this and great job with the fabrication/machining on those brackets! I ground down the polys and factory mount as you did and there close but rather fab something up and not worry about it.

Iv'e bottomed out my car over 100 times for sure, theres this one road that goes down like a roller coaster where I live and you hit 80 in a 35 real quick. When you hit the bottom it launches like a rocket and the back end slams not hits slams. lol. Guess it's 35 for a reason.
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Old Mar 17, 2016 | 06:35 PM
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Originally Posted by LS6427
Yes, I have 315's...since 2002. And I'mn lowered on G2 Super Springs quite a bit.
Did not roll my fenders.

I may have bottomed out before or maybe the axle hit the car, but man I never feel or hear it. Might have happened. Theres no visible contact spots anywhere.

Maybe I should go to the junkyard and get some bumpstops and cut them down some and put them back in....just in case....lol.

.
Well that surprises the hell out of me.
What wheels do you have and do they tuck up under the fender at all or are they pretty flush with it?
On that same note then did you have to do the BFH mod to the inner fenders so the 315s wouldn't rub there?
Got any close up pics of your rear ride height? This is interesting...
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Old May 6, 2017 | 02:55 PM
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Originally Posted by xny1989
I've seen a thread here where the person installed the bumpstops on the flat part of the rear end facing upwards. I've been running 315's for about 8 months without bumpstops and I can tell you that my tires will bottom out on my rolled fenders before the rear end hits the frame.

I just my 315s on my widened ws6 wheels and the bumpstops are into the wheel about 1 inch maybe 3/4. So I can't grind any way bc it's not close.

Anyone else run no bumpstops?
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Old May 15, 2017 | 05:40 PM
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blackduc ever consider making and selling thes?
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Old May 15, 2017 | 10:35 PM
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Originally Posted by cancam99ss
blackduc ever consider making and selling thes?
I did long ago but the factory doesn't weld the nuts in the same place so the holes would be different for all cars...... but they could be slotted for a universal fit. There wouldn't be any profit in it. I used to go to the junkyard a lot and if I saw really nice bumpstops, I always purchased them and put them in a shelf. I did notice that a set that I pulled off an 80s f body was almost 1/2" taller. Not sure if they were replaced or still one though.
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