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Some time ago I sent some of my brake parts to a company to overhaul. Brake levers etc. It seemed like a good idea at the time. They didn’t do a good job with the levers and the company has since gone out of business.
I now have over size holes in the levers which leave too little surrounding metal. See photo. The two on the left are the worst. The holes with the bushes are fine, it’s the others that take the forks that aren’t. They drilled out the forks and put in oversize bolts. They should have 5/16 inch bolts. They are now 3/8 inch and a loose fit at that.
The parts have sat on the shelf ever since to be dealt with another day.
The forks can be easily replaced. What to do with the castings though. Replace them seems the best option. I tried a company that specialise in Girling parts back to the 1930s but they don’t recognise the casting numbers or any of the levers in the photo. It seems they are unique to Lagonda?
Does anyone know of a source for these or have an alternative solution? Or do I have to get some new ones cast?
David
Hi David;
I’m toying with the idea of brazing in thin steel sleeves on mine. The net result should be close to original strength.
Alec3D printing, would that work?
For metals, that would be laser sintering. Very expensive! If I had to replicate parts like these, I think I would build them up from individual simple machined shapes welded together, then hand-finished to resemble castings. Once painted, they would look OK.
This may help – It’s at least in the UK!
http://www.3trpd.co.uk/dmls.htmThanks for the replies.
Machining from solid has been suggested to me. The two on the left could easily be one piece. Not sure I like the idea of having the other 2 welded in sections. I am not an engineer but I’m not convinced I want to rely on welds. . . .
Would casting be hideously expensive? I could make suitable patterns.
I have noticed that the holes in the short arms of the third lever in the earlier photo are not equally spaced either side of the pivot point (see new photo). This lever goes between the front axle in line with the brake pedal (ie right hand side). I can’t think of a reason for this? The inequality will be evened out by the fact that it’s floating, but why unequal in the first place? A bad casting perhaps? The holes have been drilled out by the previously mentioned “restorer” but never could have been equal.
David
The 3 points are not in a straight line either. My hazy recollection of welding is that the join is stronger than the pieces joined
Indeed they’re not in a straight line. I can’t see that it really matters the unequalness or am I missing something? Probably just a not very well made part?
Is getting the holes welded by a specialist and re-drilled a really bad idea ???
David
Won’t the effort applied to each drum be different?
Hi Chaps
Some thoughts:
I am not comfortable with making these items as castings. Originally they would have been forged so personally I think it would be better to go to a specialist welder the re-do the eyes on the original ones. Perhaps with a X-ray test afterwards to confirm integrity.
If you are forced to have some bits machined out of solid, look at various structural steel sections such as RSJ’s and U sections to see whether new levers can be carved out of a standard section. These will have been hot-rolled so the grain of the material will be better than something machined out of a solid lump.
I am not a mechanical engineer or metallurgist so do not rely on my inputs without further advice…
Colin M34
Interesting topic!
My experience on my 1933 16/80 is that the original Lagonda machining was first class – must have been a tough place to be an apprentice. Holes are where they should be and individual parts are made to high standards of accuracy and practice. I don’t know about the new company’s standards…
The oddly-spaced holes may have been to direct more of the braking effort to the front, but I’m not familiar with the LG45 brake layout so that’s just a guess.I’m a mechanical engineer, not a metallurgist, but my two cents’ worth is:
With old castings and forgings, it’s hard to be sure what the composition of the metal really is. This does mean that your weld repair should be done by someone who really knows their stuff. Cast steel should be every bit as good as its wrought counterpart for tensile strength and ductility (except that it won’t have its yield strength raised by cold working). The same steel, but forged, will have somewhat better strength in the direction of metal flow, but forging was probably chosen more for cost reasons than for better properties.
As I said in an earlier posting, if I have to repair a worn hole, I will do it with brazing in a thin steel sleeve. The temperature for brazing is well below anything that will cause trouble for the lever metal, whatever it is, and the braze strength approaches that of steel. To me it’s the least risky option.
Having said that, there are many ways to solve the same problem!
AlecHi Guys
I agree with Alec’s comments – especially his comment about brazing in a sleeve being the least risky solution. As an electrical engineer I love it when a well-fluxed solder or brazing joint gets to the right temperature and the metal runs in nicely. As Alec says, this takes place at a much lower temperature than welding and you build a second sight when this is correct. This is most satisfying.
Colin
Many thanks for all the comments.
In the end I spoke to LMB in Belgium. I felt as a Lagonda specialist they’d do a good job. They are now done and I await their return.
I will post some pix when I have them back.
David
For some reason I didnt see this post originally.
I had a similiar problem on a different car. I did not have the brake levers I required but I knew all the correct dimensions etc. I also had some originals as patterns.
The 2 levers on the left of the original photo of this post would be fairly simple to make.
I made them out of EN 24T. First I got a supplier to sell me a block of EN24t – roughly the correct overall size. I used the lathe to make the larger central hole and then drilled the other holes separately.
Then I spent a long time cutting /filing the correct shape.
Job done !
I think you could also make the 3rd from left lever in the photo in the same way.
The one on the right would be more difficult but could still be carved out of a solid block.
I was advised beforehand that EN24T was perfectly strong enough for the job and probably stronger than the original anyway !
Any comments from the metallurgists among us ?Thanks Bill for your suggestion. As you say the first two wouldn’t be hard to cut from solid. The other two would need a fairly big chunk of steel – the bottom bar in the third lever is foreshortened in the photo and in reality is about 2.25 inches long and would be a lot to cut away. I suppose you could turn the main tube on a lathe once the bulk of the metal was removed, and then bore the long hole. Third one would also need a large block. I’m sure it could be done, but time consuming.
What did you use to cut the bulk of the unwanted steel away?
David
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