Does this matter?

[dspur]

Shaft opening in new master cylinder is slightly larger than the old one. See photos Will this work or do I need to resource another master cylinder? If so, where can I get an OEM looking one…?

Old one tight (normal). New one loose.

Thanks

 

[R413]

Looks fine. The rod end is round and will fit tight into the round ended bore in the piston, held in place by the rubber retaining ring.

Your old one has the rubber at the end of the piston filling the gap, which is wrong.

Do you like that pitting on the pushrod? Is the camera making it look worse than it is?

 

[dspur]

Fine. Old one has the rubber on the end making it tighter.

domyou like that pitting on the pushrod? Is the camera making it look worse than it is?

Pitting isn’t very deep. Cleaning and repainting it prob makes it look worse in the pic. Thanks

 

[Don67Satellite]

If the push rod is loose in the bore with the rubber retaining ring on the shaft, the bore is too large. I had a similar issue replacing a MC, bore wasn't right for the push rod. Ordered the MC from Doctor Diff and worked perfectly.

 

[khryslerkid]

Pitting isn’t very deep. Cleaning and repainting it prob makes it look worse in the pic. Thanks

What R413 is saying when he stated the O-ring location is wrong, the O-ring needs to go in the groove on the push rod and then push it back into the piston until it locks in.

 

[Don67Satellite]

^^This. Looks like the same issue I had with the first "compatible" MC I got, didn't have the "lock in" groove in the bore for the rubber retainer.

 

[dspur]

What R413 is saying when he stated the O-ring location is wrong, the O-ring needs to go in the groove on the push rod and then push it back into the piston until it locks in.

View attachment 1505060

Yeah it is on there correctly. Opening too big and it will not lock.

 

[khryslerkid]

Yeah it is on there correctly. Opening too big and it will not lock.

I didn't know they had different size bores. Learn something new again.

I wonder if it would hurt to use a bigger rubber?

(Here comes the wise cracks)

 

[Don67Satellite]

Yeah I didn't realize they did either at the time, until inserting the push rod was like throwing a hotdog down a hallway.

The Doctor Diff MC is a perfect match for the manual push rod. Even includes a new rubber retaining ring. Also light as a feather compared to the OEM I took out.

"Piston is bored to accept manual brake push rod retaining ring. Master is also compatible with power brake boosters.

You can reuse your original manual brake push rod."