Is this an acceptable patch? : MGB & GT Forum : The MG Experience

Is this an acceptable patch? #1
RobertsMGB Bob RobertsMGB Berne, NY, USA Sign in to contact 1954 MG TF 1963 MG MGB MkI 1969 MG MGB GT 1970 MG MGB	Topic Creator (OP) Oct 29, 2014 08:08 PM Joined 18 years ago 877 Posts

You're looking at a rusted cross member from the back on the passenger side. The cross member half repair piece isn't long enough to repair this as it doesn't even fix the rusted hole on the right. I'm thinking I'll weld a repair patch over the rusted area. Will that be an acceptable patch or do I need to do more?

Bob Scardamalia
Albany, NY
'63 MGB #4754
'69 MGB-GT #180279
'70 MGB
'54 MGTF #2259

IMG_20141029_203655_325.jpg 28.1 KB

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #2
mgbanthony Anthony Henderson Eastern Thousand Islands, ON, Canada Sign in to contact 1962 MG MGB 1974 MG MGB	Oct 29, 2014 08:21 PM Top Contributor Joined 18 years ago 13,235 Posts

Looks like a candidate for the full cross member replacement panel. If the rest of it is rock solid except for this spot you could cut back to good metal and form and fit a butt welded patch. The cross member is a structural piece so should be repaired in a "good as new" way.

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #3
herculesmgb1971 gerard boulanger Hercules, CA, USA Sign in to contact 1971 MG MGB MkII	Oct 29, 2014 08:25 PM Joined 12 years ago 924 Posts

It does not look good...

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #4
RobertsMGB Bob RobertsMGB Berne, NY, USA Sign in to contact 1954 MG TF 1963 MG MGB MkI 1969 MG MGB GT 1970 MG MGB	Topic Creator (OP) Oct 29, 2014 08:26 PM Joined 18 years ago 877 Posts

I wouldn't say the rest is "rock solid" but this is the only place where it's rusted through. I assume that cutting out the rust and butt welding is better than patching over top.

Bob Scardamalia
Albany, NY
'63 MGB #4754
'69 MGB-GT #180279
'70 MGB
'54 MGTF #2259

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #5
rocannon rocannon L Comanche County, OK, USA Sign in to contact 1967 MG MGB GT "GT From Hell"	Oct 29, 2014 08:45 PM Top Contributor Joined 14 years ago 12,650 Posts

Robert,
If that's the front suspension crossmember, I'd first see if you can source a good replacement. That rusted crossmember is quite likely to warp and twist as you weld on it unless you control the heat very carefully.

In reply to # 2837866 by RobertsMGB You're looking at a rusted cross member from the back on the passenger side. The cross member half repair piece isn't long enough to repair this as it doesn't even fix the rusted hole on the right. I'm thinking I'll weld a repair patch over the rusted area. Will that be an acceptable patch or do I need to do more?

Pogo is right.
—————————————————————-
The power of reasons is an illusion. The belief will not change when the reasons are defeated. The causality is reversed. People believe the reasons because they believe in the conclusion.

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #6
RobertsMGB Bob RobertsMGB Berne, NY, USA Sign in to contact 1954 MG TF 1963 MG MGB MkI 1969 MG MGB GT 1970 MG MGB	Topic Creator (OP) Oct 29, 2014 08:50 PM Joined 18 years ago 877 Posts

No, Frank, it's not the front suspension. It's the cross member midway in the car from jack point to jack point.

Bob Scardamalia
Albany, NY
'63 MGB #4754
'69 MGB-GT #180279
'70 MGB
'54 MGTF #2259

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #7
rocannon rocannon L Comanche County, OK, USA Sign in to contact 1967 MG MGB GT "GT From Hell"	Oct 29, 2014 09:02 PM Top Contributor Joined 14 years ago 12,650 Posts

Oh, what I think of as a frame rail. Can't see you'll have a problem then. Butt welded patch is the way to go.

In reply to # 2837916 by RobertsMGB No, Frank, it's not the front suspension. It's the cross member midway in the car from jack point to jack point.

Pogo is right.
—————————————————————-
The power of reasons is an illusion. The belief will not change when the reasons are defeated. The causality is reversed. People believe the reasons because they believe in the conclusion.

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #8
Rick Fawthrop Richard Fawthrop Langley, WA, USA Sign in to contact 1960 Austin-Healey Bugeye Sprite 1974 MG MGB 1994 Mazda Miata	Oct 29, 2014 10:46 PM Top Contributor Joined 12 years ago 6,690 Posts

Depends on what you find when it is cut open.

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #9
dipstick Kenny Snyder (RIP) La Center, WA, USA Sign in to contact 1941 Ford N-Series 1958 MG MGA 1500 Coupe "Rosie" 1970 MG MGB GT "Pat's GT" 1971 MG MGB "Gifted To Me" & more	Oct 29, 2014 11:16 PM Top Contributor Joined 15 years ago 7,564 Posts

If you do weld it, butt then maybe fishplate, do as much of the welding as possible with the crossmember firmly bolted in place to limit distortion. After welding, however much, allow the piece to cool to room temperature prior to removing the frame rail attachment bolts. Stitch welding, 1" here, 1" over there, back and forth will help balance the weld shrinkage distortion.

Have a water bucket with a towel in it in case of fire. Button the top button on your jacket. smoking smiley

Be safe out there.
Kenny

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #10
ErnieY Ernie Y Albatera, Alicante, Spain Sign in to contact 1976 MG MGB GT	Oct 30, 2014 02:17 AM Top Contributor Joined 12 years ago 19,528 Posts

It's not good but equally it's not as bad as one or two suggest and no reason why a properly welded patch shouldn't work.

If it were me though I think I'd buy a cross member from Heritage and use as much of it as was necessary do the job properly.

http://www.bmh-ltd.com/MGBFrt.htm

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #11
Donthuis Don van Riet Rijswijk, ZH, Netherlands Sign in to contact 1972 MG MGB MkIII	Oct 30, 2014 05:46 AM Top Contributor Joined 10 years ago 13,325 Posts

I presume you won't be using the jackpoints and the factory jack anymore?!

It is a strange construction, even with a carbody in sound condition (JT warns against using it at all), let alone with these kind of body parts for support... confused smiley

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #12
tony53 Tony Graham Glen Alpine, Australia Sign in to contact 1976 MG MGB "@@#&**@"	Oct 30, 2014 05:46 AM Joined 15 years ago 558 Posts

In reply to # 2837887 by RobertsMGB I wouldn't say the rest is "rock solid" but this is the only place where it's rusted through. I assume that cutting out the rust and butt welding is better than patching over top.

Place a fillet over the top or indies to create a flange if you don't want to see it. Both add the extra strength needed

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #13
riley1489 Bruce H Great White North, QC, Canada Sign in to contact 1953 Jaguar XK120 1959 Riley 1.5 "King George" 1973 MG MGB	Oct 30, 2014 06:54 AM Top Contributor Joined 12 years ago 26,274 Posts

Procure a new one you will be grateful. The flanges of this cross member help to locate the floor panel height, jacking points etc. It appear that you have the car pretty much stripped so go for it. winking smiley

Bruce

Life's most persistent and urgent question is, "What are you doing for others?"

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #14
RobertsMGB Bob RobertsMGB Berne, NY, USA Sign in to contact 1954 MG TF 1963 MG MGB MkI 1969 MG MGB GT 1970 MG MGB	Topic Creator (OP) Oct 30, 2014 08:02 AM Joined 18 years ago 877 Posts

Thanks all. Yes, much of the car is stripped because we've already replaced sills and rockers on the DS and the floor boards were going to be next. I'll have to sleep on whether to tackle replacing the entire cross member.

Bob Scardamalia
Albany, NY
'63 MGB #4754
'69 MGB-GT #180279
'70 MGB
'54 MGTF #2259

Reply

Was this post helpful or interesting?

Yes No Thank

Re: Is this an acceptable patch? #15
mike.l mike l tillsonburg, Canada Sign in to contact 1952 MG TD 1954 IHC L-Series 1954 Nuffield PM-4 Tractor 1957 Morris Tractor (Nuffield) "Little Brother" & more	Oct 30, 2014 08:28 AM Joined 11 years ago 602 Posts

Hi if you are going to replace the floor pans then that is the time to replace the cross member as you will be undoing all of the spot welds to remove the floor just a few more on the ends to remove the cross member and then its set right for another 40 years with a little care patch welding is only temporary at best mike

Reply

Was this post helpful or interesting?

Yes No Thank

MGB & GT Forum

Is this an acceptable patch?

To reply or ask your own question:Members Sign InorCreate an AccountRegistration is FREE and takes less than a minute

To reply or ask your own question:

or

Registration is FREE and takes less than a minute