Broke the throttle on the six, need CSOB ideas Options

[djm914-6]

It's been a long time comming I suppose. The lever that the pedal pushes on has been tilting to the inboard until the throttle rod rests againts the floor board. Sometimes I'd attempt to bend it back, but most of the time I'd just del with the squeeking.

Well, there's no more squeek because the throttle lever of the pedal assemble broke off. I got the car home by bending he manual throttle lever just enough to catch the throttle cable end. I drove it by pulling back on the lever.

Now, I need some ideas. I know that the six lever isn't so common. What's the changes of having this one welded up and reattached to the pin that goes into the pedal assembly?

[ClayPerrine]

Contact Rich Johnson. He had 5 factory throttle bellcranks for 914/6s. I know. I sold them to him.

[r_towle]

post a pic...never seen one...if it can be welded, bring it on by...

Rich

[mightyohm]

Are the pedal assemblies for the sixes really different? I doubt it.

Weld it up or find a donor 914 pedal cluster.

[Aaron Cox]

the pivot plate that the gas pedal connects to is different

[djm914-6]

Hey Rich, What's the chances that a weld would hold?

I'd love to just buy a "new" one, but today was also my last day as my job too. Oh, I just love days like these.

[Eric_Shea]

The crank isn't different except for the handthrottle plate that's spot welded to it.

The rod that is broken (the lower left in the picture) is brazed (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way) in the bellcrank assembly. They usually make a clean break. And people usually screw them up by trying to weld them with a MIG or other device.

The very best CSOB solution is to have everything cleaned up nicely and take it to a local shop that does brazing (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way). I doubt they would charge you more than $10 bucks to braze it back up.

It's hard to braze (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way) it properly unless it's really clean. The brazing doesn't like to take because it was plated after the factory brazed it. Clean it up with some fine files and make sure the plating is removed. It should braze (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way) up fine after that.

Any good welding shop should be able to take it from there.

Here's one I built last weekend. I used a -4 crank and a piece from the engine lid.

[r_towle]

QUOTE (djm914-6 @ Nov 8 2005, 09:05 PM)

Hey Rich, What's the chances that a weld would hold? I'd love to just buy a "new" one, but today was also my last day as my job too. Oh, I just love days like these.

cant say till i see a pic.

Probably pretty easy, but it depends upon what broke.

Rich

[lapuwali]

QUOTE (Eric_Shea @ Nov 8 2005, 06:08 PM)

The crank isn't different except for the handthrottle plate that's spot welded to it. The rod that is broken (the lower left in the picture) is braised in the bellcrank assembly. They usually make a clean break. And people usually screw them up by trying to weld them with a MIG or other device. The very best CSOB solution is to have everything cleaned up nicely and take it to a local shop that does braising. I doubt they would charge you more than $10 bucks to braise it back up. It's hard to braise it properly unless it's really clean. The braising doesn't like to take because it was plated after the factory braised it. Clean it up with some fine files and make sure the plating is removed. It should braise up fine after that. Any good welding shop should be able to take it from there. Here's one I built last weekend. I used a -4 crank and a piece from the engine lid.

That would be "brazing", which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way.

"Braising" is a way to cook meat.

OK, I'll stop now...

[r_towle]

brazing is also much weaker than welding.

Rich

[fiid]

Much is a deceptive word. It's possible to get 70,000psi strength braze joints and 130,000psi is possible with stainless. I don't know what the numbers look like for welds though.

Brazing is also much lower temp than full on welding, so it's easier not to induce warping or material defects.

Brazing is crap at butt joints however. It's much better when there is an overlap.

You can also braze stuff reasonably easily with a little MAPP/Oxygen setup from Home Despot.

Personally - though - I much prefer the MIG.

[Eric_Shea]

Fixed... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif)

Being in the pedal biz, I've seen 1/2 dozen weekend weld jobs on those bell cranks (is that what they're called James?) I'd hate to see that happen to a -6 piece. But, here's where I exit stage left... it ain't my car.

P.S. Not trying to dis your welding work... I've just seen a lot of bad ones. Hell I even tried it myself. I take all mine to Troy and have him "braze" (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way) them.

[lapuwali]

QUOTE (fiid @ Nov 8 2005, 06:58 PM)

Brazing is crap at butt joints however. It's much better when there is an overlap.

I disagree with that. When I said scads of racing chassis, I meant spaceframes. All built using lots of small round tubes fishmouthed and butt welded together, sometimes joining a good number of them into one joint. The lower temps obviously helped in reducing warpage problems when joining a lot of tubes together. And when I said scads, I meant SCADS. Most of the F1 frames built from 1950 to 1965 were brazed spaceframes. They went to monocoque construction after that, but minor formulae, like Formula Ford, continued to use brazed spaceframes until relatively recently. A good number of aircraft frames were also made this way. The fillet of bronze at the joint naturally had a nice radius, which meant it wasn't a stress riser, which a normal weld bead will be.

Brazing can also join two dissimilar metals together, which you cannot do with fusion welding.

I have a very nice book on motorcycle chassis design, written by an engineer that designed a number of racing bikes that did quite respectably in the 70s and 80s, which advocates brazing as generally superior to any other method for making spaceframes. TIG is probably better, really, but brazing shouldn't be discounted.

[lapuwali]

QUOTE (Eric_Shea @ Nov 8 2005, 07:00 PM)

Fixed... (IMG:http://www.914world.com/bbs2/html/emoticons/dry.gif) Being in the pedal biz, I've seen 1/2 dozen weekend weld jobs on those bell cranks (is that what they're called James?) I'd hate to see that happen to a -6 piece. But, here's where I exit stage left... it ain't my car. P.S. Not trying to dis your welding work... I've just seen a lot of bad ones. Hell I even tried it myself. I take all mine to Troy and have him "braze" (which is connecting two bits of metal using more heat than soldering, but less heat than welding; a filler material is added, usually bronze. The British usually call it "bronze welding", and scads of racing chassis were (and are) assembled that way) them.

Thank you. (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[Eric_Shea]

QUOTE

but brazing shouldn't be discounted

Or misspelled! (IMG:http://www.914world.com/bbs2/html/emoticons/w00t.gif)

[r_towle]

QUOTE (fiid @ Nov 8 2005, 09:58 PM)

Much is a deceptive word. It's possible to get 70,000psi strength braze joints and 130,000psi is possible with stainless. I don't know what the numbers look like for welds though. Brazing is also much lower temp than full on welding, so it's easier not to induce warping or material defects. Brazing is crap at butt joints however. It's much better when there is an overlap. You can also braze stuff reasonably easily with a little MAPP/Oxygen setup from Home Despot. Personally - though - I much prefer the MIG.

bronze is weaker than steel.
Bronze is brazing, or soldering..it is using a liquified metal alloy to glue to pieces together.

now, if the piece in question has beenbroken off ina butt joint way..or torn off, there is no reason that welding with steel mig wire, or tig...would do any harm to this piece.

I have always been a CSOB,,,if the part is an original brazed 914/6 part...get it brazed...

If the part broke(not at a brazed joint, because it would never break....brazing is so tough) then fix it with welding.

I discount brazing because of the following facts.

You cannot get paint to stick to brazing...it will always lift off, so will bondo..ask any body guy about brazing and paint....

If brazing was better than welding structurally, bridges, cars, buildings, and a wide variety of other steel connections would be done with brazing because its easier, cheaper and would produce less heat and less warping etc...

but its not the right method to fix a broken piece of steel that is under stress...

Rich

[Eric_Shea]

Your 914 is brazed (and they painted right over it)... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

There's usually two ways they break:

1. They rip (the stamped metal portion of the bell crank) down there by the rod or,

2. The brazing breaks loose. Hopefully the brazing has simply broken loose and it can be rebrazed.

The brazing does break there... it usually takes about 30 years but it can break.

[r_towle]

QUOTE (Eric_Shea @ Nov 8 2005, 11:09 PM)

Your 914 is brazed (and they painted right over it)... (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

the defense rests! (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

[fiid]

QUOTE (lapuwali @ Nov 8 2005, 07:14 PM)

QUOTE (fiid @ Nov 8 2005, 06:58 PM) Brazing is crap at butt joints however. It's much better when there is an overlap. I disagree with that. When I said scads of racing chassis, I meant spaceframes. All built using lots of small round tubes fishmouthed and butt welded together, sometimes joining a good number of them into one joint. The lower temps obviously helped in reducing warpage problems when joining a lot of tubes together. And when I said scads, I meant SCADS. Most of the F1 frames built from 1950 to 1965 were brazed spaceframes. They went to monocoque construction after that, but minor formulae, like Formula Ford, continued to use brazed spaceframes until relatively recently. A good number of aircraft frames were also made this way. The fillet of bronze at the joint naturally had a nice radius, which meant it wasn't a stress riser, which a normal weld bead will be. Brazing can also join two dissimilar metals together, which you cannot do with fusion welding. I have a very nice book on motorcycle chassis design, written by an engineer that designed a number of racing bikes that did quite respectably in the 70s and 80s, which advocates brazing as generally superior to any other method for making spaceframes. TIG is probably better, really, but brazing shouldn't be discounted.

Hmm. I'll yield to scads (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif). I saw a brazed chassis once made of box steel where each joint was made by wrapping the top and bottom of the piece it was intersecting. That was a high-school project though so probably not up to F1 standards (IMG:http://www.914world.com/bbs2/html/emoticons/wink.gif).

[djm914-6]

Still no pics of the carnage as I haven't taked the time to remove the parts (except for the brokem part of the throttle).

I think after reading this thread and looking at Erics work, that I should just got for a complete cluster. The part that broke on my car isn't just that it came off the pin, but the upright piece itself snapped. I'll remove the assembly and have Rich take a look at it. If it can be repaired with welding for the time being then great, It'll give me time to save my pennies for a rebuilt cluster. If not, then the car will sit.

Thanks to Rich for offering to help and to Eric for his service to the 914 community.