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I was on a road trip when the hydraulic line to the clutch master cylinder popped out. Kinda eerie when the pedal goes right to the floor and stays there. Fortunately I was able to land it in a good spot and stall out the truck by breaking hard!
The hydraulic line has an end fitting with a groove with a gasket on it. you push it in to the master cylinder and a roll pin keeps it in place. The roll pin failed and the line popped out. I was trying to replace the roll pin but the auto parts stores don't carry that part. You have to by a master cylinder to get the 30 cent pin. I replaced the roll pin with a cotter pin of about the same diameter and it got me off the side of the road and home! I also noticed that the groove in the end fitting was worn where it interfaced with the roll pin. I rotated the fitting 90 degrees to some fresh groove. That should last another 400,000 miles.
I'm thinking to replace that cotter pin with either the roll pin, if I can find one, or perhaps a better fitting cotter pin. I used one with 1/8" diameter and I think the roll pin was slightly larger than that, perhaps 5/32" or so. Anyone know the size and or part number of the roll pin? Any reason I shouldn't use a cotter pin of the same diameter as the roll pin?
I'm thinking to replace that cotter pin with either the roll pin, if I can find one, or perhaps a better fitting cotter pin. I used one with 1/8" diameter and I think the roll pin was slightly larger than that, perhaps 5/32" or so. Anyone know the size and or part number of the roll pin?
I happen to have a new master cylinder and pin here to measure for you.
The roll pin is 0.625" long, and the OD is 0.131"
The ID of the hole in the master measures 0.128" on my vernier.
I have some alignment punches here, and a 1/8" pin slides easily through the hole, and a 9/64" pin will not fit through it.
Thanks for the info, very helpful! It makes sense that the pin is bigger than hole. I do remember pressing it in when I replaced the master cylinder, negative fit up. Now back home I'm measuring the OD of my master cylinder to be the same as you measured for the pin OD. I guess if it's been in there a while they become the same, especially with a bit of wear.
I think I'm going to go with the largest cotter pin I can fit in there and call it good. A new replacement pin might not be tight enough to stay in and the cotter pin is secure. What do you think?
I decided to use a piece of round stock. I honed it down to about .132 and put a 90 degee bend in it. Then press fit it in. Seems a better idea than the cotter pin since it's split. More solid than a roll pin I suspect. That should do it until it's time to replace the master cylinder.
Says 7.3 L on the valve cover but really a 6.9 L, in case anyone noticed.
I decided to use a piece of round stock. I honed it down to about .132 and put a 90 degee bend in it. Then press fit it in. Seems a better idea than the cotter pin since it's split. More solid than a roll pin I suspect. That should do it until it's time to replace the master cylinder.
That'll do the trick just fine I'd say. Long as it won't fall out, it will do it's job.
She's in there good. One of the reasons I went with the bend is to allow me to wiggle it while pushing. And remove it when needed too. If it wears well it might survive to the next cylinder. No tool needed to install or remove. I also got plenty of extra length so can keep an eye on it...but not expecting it to walk out.
11-12-2018, 12:04 PM
