Bravo 1 top cap oil leak
 

One of my bravo's keeps on blowing the top cap o-ring and leaking oil. I service both drives the same way. What could be the cause of this? I would imagine pressure is being built up in the failing drive. It almost looks as if the o-ring is being pinched on assembly but i am sure that is not the case what could be causing this?

Is it the small o-ring? If it is, don't use any grease or sealer because it will squeeze to the inside. Just clean the groove and set it in dry.Use Perfect Seal on the large o-ring but nothing on the small.

It's the large o-ring that is blowing. Not using any sealer on assembly, should I? The cap and case look to be perfect.

What year drive and what motor is it? Sounds loke the top cap is "walking" around under load. May need to put a billet cap on or use Imco's top cap mod.

BTW, are you using Merc orings?

89' 7.4 330's 300hrs 1.5 B1's 25p mirage 4900rpm max, yes Merc o-rings. Is there any thing that would cause a pressure build up at this point? Is a bravo sealed or is there a vent. I though I remember somthing about problems with the cap on the res. bottle?

Thanks for your input

Is the drive w/ L.H. prop blowing the o-ring?

port side, props turning out. Goto go for a bit will check back later.

Thank you marinetrans

Russ

Sounds like the top cap is moving around.Makes sense beacuse its the port side w/ L.H. prop. Put on a billet cap w/ stud kit.Billet Marine, Max Worx, Teague all make good billet caps.

ditto on marinetrans

Hey Russ,
The Bravo is designed to work under pressure. If you have a leak any where you will see the Gear Lube bubble and rise in the reservoir. Not sure why you are having O-ring problems. Are you torquing the Drive on tight enough?
Dan

Russ SR1,
My recent purchase had the same problem (96 with Bravos). Turns out the oil in the drives hadn't been serviced properly. If you look closely at the base of your reservoir you may find what I did (a thick sludge).

When the drives warm up, the oil expands and tries to go into the reservoir. The reservoir cap has a vent to relieve this pressure. When the pressure reached the sludge it built up until it blew through the sludge and popped the cap off. I removed and cleaned the reservoir, completely drained the drives and replaced drive oil and topped off to level. I've never had a problem since.

Hope this helps!

Thanks marinetrans I will try it out.

boatnick I will take a look, sure hope theres no sludge anywhere on the formula

Hey Dan how are you and Vicky doing? Baby Shannon came out fine last Sept. so this year the boating might get back to normal. Great thing about it, the wife said go buy a bigger boat with more cabin. So boat shopping I am. I can't wait to see everyone on the water this year.