Brake "anchor" bolts

Information relating to the Matchless G2 or AJS Model 14 250cc Lightweight
56G80S
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Re: Brake "anchor" bolts

Post by 56G80S »

On the topic of the stays themselves, I'm still using the one that came with the G80S which is the straight rather than spatula shape and should I have need to replace it I would use the spatula shaped one.

Very sound point about the ovality but also take a look at the fit where the top holes go over the two studs on the fork slider as there can be wear there.

At the risk of re-creating a thread from a long time ago these should be studs not bolts and worth giving that area of the slider a good clean up and checking for cracks particularly if the motorcycle is new to you. However there was also a long previous thread about which side of the mudguard brace the stay should be; personally I stick with up against the slider.

I will have to buy some thread gauges.

Johnny B
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Rob Harknett
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Re: Brake "anchor" bolts

Post by Rob Harknett »

Johnny, the front guard is fixed by 4 bolts not studs, that includes the torque arm side . If you fit studs you will have to remove studs to get the guard off the forks. Parts list will confirm 4 bolts ( note they are 22 tpi thread in alloy, not 26 cycle ) The torque arm can only go flat against the fork slider, it will not fit flat against the guard.
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dave16mct
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Re: Brake "anchor" bolts

Post by dave16mct »

Sorry Rob but I agree with Johnny, its ( from the 62-65 supplement lightweights) 010624 stud, bridge to slider (2), 010795 bolt, bridge to slider(2)
Same as heavyweights. I agree its very difficult removing the mudguard.
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robcurrie
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Re: Brake "anchor" bolts

Post by robcurrie »

A screw is tightened by applying torque to the head of the fastener, a bolt is tightened by holding the head of the fastener and applying torque to the nut on the fastener. Full or partial thread doesn't come into it.

Rob C
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Rob Harknett
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Re: Brake "anchor" bolts

Post by Rob Harknett »

dave16mct wrote:Sorry Rob but I agree with Johnny, its ( from the 62-65 supplement lightweights) 010624 stud, bridge to slider (2), 010795 bolt, bridge to slider(2)
Same as heavyweights. I agree its very difficult removing the mudguard.
Dave.
Ashampoo_Snap_2016.07.10_20h03m06s_001_.png
1941 to 1959 No studs mentioned here
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Andy51
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Re: Brake "anchor" bolts

Post by Andy51 »

Arghhh, don't do that, Ben. If someone has used a 3/8 UNF 24 tpi bolt (use a thread gauge or count the threads against a rule) then the female threads (26 tpi) will have been seriously b*******d and your screw could easily strip or work loose. The screw is mainly acting in shear, so it may have held so far, but if it comes loose it won't matter which torque arm you have fitted!! Get the female thread helicoiled, replace the steel bush or get a replacement brake plate but don't fit a wrong thread in such a critical location! Andy
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Duncan
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Re: Brake "anchor" bolts

Post by Duncan »

Its on the next page Rob:
1959 Parts list page 47.PNG
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Janet
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Re: Brake "anchor" bolts

Post by Janet »

To go back to the original query, I have found in Christian's archives a reference to this bolt in the supplemental spares list for the 250CS and the G5, the earlier models having, I believe, lugs between the brake plate and the fork leg instead of an anchor arm, similar to that on the rear wheel. On the G2CS and G5 lightweights the part number is shown as 014807. Unfortunately there is no mention at all of it for the CSR so it may or may not be the same. The only way to find out would be for someone else with a CSR to buy one of these bolts and try it so Ben would know whether it should fit his.
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BultacoBen
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Re: Brake "anchor" bolts

Post by BultacoBen »

Good advice Andy, will get it helicoiled. Offending screw is definitely 24tpi and replacement bolt is 26tpi.

So it looks like the heavyweight anchor bolt 014807 in 3/8" 26tpi and 5/8" long would fit the lightweights, including mine IF someone hadn't buggered the threads... EDIT: Janet, looks like I've answered the question then, it should fit!

For the record, my sliders have studs not bolts, and the bridge is removed easily as it has slots rather than holes which slide down over the studs. Ken de Groome says: a feature of all the studs which screw into aluminium on AMC machines (except the tappet inspection covers on single engines) is that they have a cycle thread on one end and a BSF thread at the other.
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Janet
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Re: Brake "anchor" bolts

Post by Janet »

I had the bolt fall out of a M18 on the way to the Polish IJR. Fortunately for me I was in a quesue of very slow moving traffic though a town so as I pulled on the front brake, it felt very odd and didn't work. I was able to steer over to the kerbside where, luckily, there were two vacant parking spaces. I knew it could have only just dropped out or I'd have known much sooner so I wandered back up the road a few yards and saw the bolt lying in the road. My luck was in and a kind driver understood what my wildly waving arms meant and stopped to let me pick it up.

Glyn and I refitted the bolt, then gobbed all round it with magic metal. I wouldn't recommend this normally but needs must. It got me the final 100 miles to the rally without further incident but was showing signs of stress when we arrived. No way was I going to ride home with it like that but Gary Corcoran lent me his front wheel at the end of the rally because he'd brought his bike in a van.

I realised how lucky I'd been when I saw Ludwig's bike. He'd had a similar problem except I think his bolt sheared off, but, unlike my snail's pace when it happened, in his case he was going at normal speeds with the obvious results. This is a photo of the damage to his front fork.
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