Joined: May 2018 Posts: 2,104 Threads: 110
Reputation:
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
Hi All
Just an update and a bit of a warning.
Soon after I posted this thread I fitted star washers on all the coupling bolts. Since then I've had bolts loosen on three occasions. The latest incident was after the run this weekend. A rumble developed particularly on power but disappeared on overrun. On inspection, one bolt had come off completely and another was loose.
Clearly star washers, (or the ones I'm using) don't work.
I've now replaced all the star washers with normal split washers.
Cheers
Howard
Joined: Aug 2017 Posts: 1,977 Threads: 90
Reputation:
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Location: Ripon
I'm told that star washers have no effect on holding nuts in place. Their best function is to create good electrical conductivity.
Joined: Aug 2017 Posts: 1,711 Threads: 47
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Location: Auckland NZ
Car type: 36 Nippy, 31 RM, 38 Special, 24 Works Rep
"Are we trying to create a problem that doesnt exist?" ....Solving these "problems" is what some Austin seven owners seem to excel at Hedd.
Black Art Enthusiast
Joined: Aug 2017 Posts: 1,337 Threads: 34
Reputation:
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Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
My experience is that properly tightened fasteners don’t come loose. In the case of a propshaft joint there has to be sufficient clamping load that all of the drive torque is transmitted in face friction not by shearing the bolts. If it is, the joint won’t come loose. If it isn’t, the bending of the bolt ratchets the nut loose. Spring or star washers won’t stop it, a split pin might but then the bolt will fail in fatigue. In this case, the bolts are more than adequate for the job, the problem with propshaft bolts is that they are difficult to tighten, but if they are tight they work.
Alan Fairless
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
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Location: Auckland, NZ
But only crushing fabric so never very tight (suspect very tight tends to cut into fabric and damage). Seems it is one application where split pins or twisted wires are well suited. Avoid the strong springy steel pins.
On other cars loose universal bolts can be very dangerous but fabric Seven ones seem unthreatening..
Joined: Aug 2017 Posts: 2,748 Threads: 31
Reputation:
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Location: Auckland, NZ
It is a long time since I changed one of these but presumably the intention is that only the split pin nuts are disturbed. Ditto when removing engine/gearbox.
Is that in fact the case or when replacing in car is there then not enough space to remove the u.j?
Without tab washers, removing the studs from the flanges may make things easier but even with a special spanner difficult to hold the thin hexagon flange of the stud with the fabric disc in place.
From an old one, which had been removed without undoing the castle nuts, and after being bolted up for years, the studs were a tight fit in the fabric and needed levering to separate.
