MK Rear uprights - Cracked!
Matt21 - 10/6/15 at 07:36 PM
Recently I had the rear wheels off and happened to notice cracks in the powder coating along the welds on the rear uprights.
I was doing a trackday a few days after this so thought it would be best to scrape off the coating and check it out properly.
And yes, both sides had actually cracked through the weld!
Thankfully my dad was free to reweld them for me.
Just another thing for people to look out for!
On this photo, the cracks ran either side of the bottom of the hole in the upright. The cause, square corners to the hole! these create very weak
points, ideally the hole would just be round (or not there at all as it isn't needed!)
SJ - 10/6/15 at 08:02 PM
I can't see the crack in that pic. Where exactly was it as I'd like to check mine?
Stu
v8kid - 10/6/15 at 08:13 PM
I can't see it either
yellowcab - 10/6/15 at 08:17 PM
Huh - I'm confused, that looks like my photo from my old car… as I was the only person that I knew of to run my rose jointed rear arms next to
the shock absorbers to improve roll centre and lower CofG...
40inches - 10/6/15 at 08:30 PM
Moving the arms up like that is fine, but ,there is now a weakness in the upright at the old wishbone mounting points.
The old crush tube should be bolted back in place to add some strength.
prawnabie - 10/6/15 at 08:46 PM
I think he is just using that photo as a reference
yellowcab - 10/6/15 at 08:54 PM
So he is… I added a crush tube in the lower hole after this pic 
austin man - 10/6/15 at 09:01 PM
The hole should have been welded up as moving the mounting higher up exerts more force lower down so the area where the hole is becomes the weaket
point, this is a failing o modifying and not reinforcing the change IMO
Matt21 - 11/6/15 at 06:48 AM
Oh sorry for the confusing... yes just google 'mk rear upright' to get a photo... there are no cracks in that one!
I forgot to get photos of mine, just welded it quickly!
basically either side of the big hole on the front, where the chunky square plate is welded on.
austin man - 11/6/15 at 07:49 PM
I still think it would be down to the additional leverage exerted by moving the shock absorber mount
prawnabie - 12/6/15 at 05:53 AM
Doesn't sound like the OP has modified his though
[Edited on 12/6/15 by prawnabie]
adithorp - 12/6/15 at 07:24 AM
quote:
Originally posted by austin man
I still think it would be down to the additional leverage exerted by moving the shock absorber mount
But is the OPs mounted like that? He's just used that picture (of yellowcabs upright) to show where his has cracked
britishtrident - 12/6/15 at 07:26 AM
General pointers to any no pros repairing a crack, don't simply weld up the crack to repair it. (1) Drill a hole (at least 2mm in dia) at the
sharp ends of crack to act as a crack arrestor. (2) Open out the crack with grinder or Dremmel. (3) Then weld up the crack. You can then weld on any
additional reinforcing plates and fillets.
Matt21 - 12/6/15 at 09:46 AM
no mine hadn't been tinkered with (from what i know anyway)
good point about the drilling and grinding.
Though mine was cracked the full length so there was no 'sharp end', simply ground it out and rewelded, and then welded again just to make
sure!