• Hi Guest! Being a Paying Supporter is NOT a requirement to participate at BCF. However, subscribing will help ensure we can continue to serve the LBC community for years to come. If you enjoy BCF and find our forum a useful resource...Please consider supporting us by **Upgrading**
    (PS: Subscribers don't see this banner)

Spridget master cylinder cap, metal


Freshman Member
I have owned my 1962 Midget since 1964, and I have had problems with the master cylinder cap leaking for many of those years. After years of use, the original metal cap has become worn and distorted, and leaking. I have tried various types of washers and gaskets to no avail. I was told to use the "upgrade" of the plastic cap that replaced the metal. It also leaks, perhaps worse than the metal. I have used an oem cap, and I bought a repro from Moss, which is a complete failure. First, the threads don't match the oem, there aren't enough of them to properly tighten the cap. It unscrews itself while you are driving and leaks the worst of all. After several discussions with them, I gave up. They insisted it was correct and didn't leak. They finally refunded my money, and didn't even want it back to be examined.
I posted the same questions on spritespot.com about the leaking cap, and one gentleman informed me that a new metal cap is being produced. He gave me some leads on google, but I have not been able to find out any recent info about the caps. I did find a member here at bcf and he had some of these caps to sell 2 years ago. I contacted him here, but I have yet to hear from him. I have heard from a number of people who still have the same problem I do with the leaking cap. I keep forgetting to check the master cylinder after every time I wipe up the leak, and I almost ran the level down to the pushrods, which sucked in some air. This has to cease, I'm getting real tired of it. Once, I thought the master cylinder itself was leaking after I rebuilt it, but it was just the cap.
I would appreciate it if someone could tell me where to get a reliable new metal cap that won't leak, preferably in the USA. I would greatly appreciate any help anyone could give me on this. I got a part number(17H3723) and it fits many vehicles, Midgets, Sprites, MGAs, Magnettes, real Minis, and others. Thanks, Russ
There are some on ebay, but I do not know if they will fix your leak. I believe the caps are made to be vented and as such you will have a slosh issue.


Freshman Member
Thanks for the reply, Trevor. As I mentioned, I have had the Midget since 1964, and there were periods of time where there has been no leaking from the cap. Do all the different vehicles that use this cap have a leaking problem? I don't recall those that I knew who had MGAs, real Minis, Bs, etc. having a leak from the cap. Does anyone know how to correct this seemingly ongoing problem? There are some that have resigned themselves to never stopping it, and placing a folded up paper towel under the master cylinder rods to catch the brake fluid so it doesn't get on their shoes. I was told by someone at spritespot.com, that there were new metal caps being produced somewhere. My original metal cap didn't leak as bad as the plastic ones, which were supposed to be an upgrade??? You don't want to tighten them too much for fear of breakage. The ones from Moss are a joke, they look like crude 3D printer work, without enough threads. My original cap doesn't appear to have an external vent. I never overfill the m.c., so I can't figure out why there would be so much sloshing around that it would force fluid past the threads. I am open to suggestions. Thanks in advance to anyone who has solved this problem and could share it with me.


Jedi Warrior
Country flag
Hi go to the Bugeye Parts Web site run by John Felt. Click on Bugeye parts new and scroll to the bottom of the first page and you will find metal caps for sale for $13.95 each. I hope this solves your problem


Freshman Member
Thanks 59diamond, but I have been there before and the seller has no more, and referred people to another site, which is known to be unreliable.

SD Bugeye

Jedi Warrior
Country flag
Make a fiber washer that just fits inside the cap.
drill a tiny hole in the middle for vent.
if the current washer is damaged or missing fluid sloshing will work it's way over the edge with no seal and out between cylinder and cap treads
but if the washer is i tack in place that keeps the threads from everi seeing fluid


Freshman Member
Thanks, SD Bugeye, What material would you suggest for the washer? I have tried a variety of washers over the years, flat rubber, o-rings, cardboard, and I tried to make my own cork washer (I can't remember how long that worked, I have had the car 51 years, and one forgets). I figured that you had to seal the edge between the cylinder and the cap, but I didn't know what material would work. The cork did work at one time, I know. I really appreciate your help with this. Being retired now, I have more time to address things on the car now that I have wanted to do. Last summer I finally got around to replacing the seal in a rear hub. I had the right socket finally and I had done them before, I just needed the time to do it. Now I have the time. Thanks, Russ
Similar threads
Thread starter Title Forum Replies Date
H '65 Spridget Master Cylinder Rebuild Issue Spridgets 2
B Spridget Triple Master Setup Racing 5
B How to clean the old gunk out of a Spridget gas tank? Spridgets 21
N Misc Spridget parts Spridgets Classified 0
N Spridget sheet metal Spridgets Classified 0
Bayless Wanted: Spridget horn button bracket Spridgets Classified 1
Michael Oritt Wanted 4.22:1 spridget differential Spridgets Classified 1
T Roy Orbison had a Spridget! Spridgets 2
I Wanted emergency brake rods from later Spridget Spridgets Classified 0
S For Sale Spridget Parts Garagea Clearance Spridgets Classified 5
Jim_Gruber Pages from Porter Spridget Restoration Manual on Seat Recovering, You Tube Videos Spridgets 3
Jer For Sale Assorted Spridget Parts Spridgets Classified 0
JPSmit Spridget thread question FORUM Help 2
Jim_Gruber Removing a Spridget Engine Checklist Spridgets 5
T Smart Car Seats in a Spridget? Spridgets 8
histerical Wanted WTB Set of Later Spridget Rear Brake Backing Plates Spridgets Classified 0
6 Spridget Radio/Speaker Case Spridgets 4
Jim_Gruber Free Spridget Windscreen available - Dayton OH Spridgets 3
FredApplerot For Sale Pace Setter muffler for 1964-74 Spridget - Brand New Spridgets Classified 5
M Hauling a Spridget - Proper tie down technique? Spridgets 15
M Period Spridget articles Spridgets 5
Branson box spridget grill mounting tabs / ears / brackets Spridgets 3
HealeyRick Ro-Spridget AutoX Spridgets 4
T Question regars 'frame assembly-hood' for various spridget models Spridgets 7
Rut Interesting non Spridget Spridgets 3
Michael Oritt Spridget Differential Carrier--early versus late question Spridgets 1
Jim_Gruber A Quality Piece of Kit for Bugsy IV - Creative Spridget Rear Disk Brackets Spridgets 8
Jim_Gruber Replacing Spridget Coolant Spridgets 21
Jim_Gruber Adjusting Spridget Doors Spridgets 4
gfholl Spridget on a stick Spridgets 0
drooartz 400 mile road trip in the 4-door Spridget Spridgets 11
drooartz The family Spridget Spridgets 10
N 60's Spridget paint? Spridgets 20
drooartz Up-date on the 4-door Spridget [Morris Minor] Spridgets 12
Trevor Jessie Any of you Spridget guys coming to MG2016 in June? Spridgets 3
R Spridget Starter Spridgets 4
T Harley-Davidson mufflers on a Spridget Spridgets 14
S Spridget Stealth? Spridgets 5
W Long time Spridget poster looking at BT7 Austin Healey 5
certifiedcarnut Are there any spridget forum members who live on maryland's eastern shore? Spridgets 1
Sopwith_Camel spridget in italian Spridgets 1
David Townsend Spridget Illustration Available Spridgets 4
Answerman Spridget transmission in the boot of a Jensen Healey Spridgets 9
aeronca65t Spridget 3wheeling Spridgets 9
aeronca65t This is a different Spridget Spridgets 6
aeronca65t Possible racer-Spridget for sale-Atlanta Racing 0
Jim_Gruber Dye for Spridget Knobs - Restoring dash Spridgets 12
W TR8 brake aclipers on a Spridget Spridgets 38
anarchy99 Hardtop question... Spridget related Spridgets 21
Editor_Reid Gifts for your Spridget Spridgets 21

Similar threads