Bugeye master cyliner questions

[Bugeye_Al]

Hi all!

It's been awhile since I last posted or put any significant time working on my Bugeye. Since last I posted, I had put in the hydraulic fluid (Castrol LMA) and bled the clutch and brake lines.

At about that time vacation and other time drains kept me away from the car. When I went back I discovered my "rebuilt" master cylinder was leaking at the joint where the top joins the body of the MC. (Item #7 on the picture below.)

The MC was rebuilt by a vendor that seems to not get rave reviews here. Also, the MC sat on a shelf for about a year before I installed it.

The leak trashed the paint on the pedal box and pedals, but luckily not the car itself. So last night I removed all fluid from the system and pulled the MC and pedal box.

Also, as point of reference for one of my questions, this car has front disc brakes.

Now here are my questions:

First, is the leak at the top plate to the MC body a typical leak point and will a new gasket be the simple fix or could this be an ongoing issue unless the mating surface are cleaned up. (I haven't removed the plate yet to assess the mating surfaces.) Is this a dry fit seal or should some form of sealent be used?

Second question concerns the conversion to disc brakes. When I had the MC rebuilt, it was before I found this website and all the knowledgeable, helpful people who post here. I questioned the rebuilder about re-sleeving the MC to 3/4" for the disc conversion but was assured by him it was not necessary and it was left at 7/8". Subsequent reading here and elsewhere, points me to a different conclusion. Should I send this MC off and have it re-sleeved at this point?

I am also currently using the stock BE rear brake set up. If I am going to go ahead and sink more money in the MC, should I go ahead and find donor parts from a later car and change over the rears? I have read differing opinions on whether this is necessary, but if I am going to make this right I would rather do it now while I have the MC out.

I know the disc conversion has been discussed a lot on this board previously, but I would like to hear from others on how well the different combinations work in actual application.

Thanks in advance!

 

[GB1]

Al

Sorry to hear of your misfortune. I have converted to front rotors and am running the later dual cylinders, so I can't help you with your leak.

As for converting the rear to the dual pistons it does not add that much benefit, but if you are running a modified engine, then I would say go for it.

I have the conversion for mine, but haven't gotten around to it. Please note that if you do the rear conversion, you will need to change the brake line as well.

I hope that this helped a lil.
Pat

 

[John Moore]

Please note that if you do the rear conversion, you will need to change the brake line as well.

Al - Sorry to hijack your thread, but I'm going to do this conversion shortly. Sierra is rebuilding and resizing my MC for my front disc and I've gotten later dual pistons and backing plates for the rear.

Pat - what's the deal with the rear brake line? Fittings?

 

[GB1]

Not the fittings, the rear cylinder location is different.

Pat

 

[John Moore]

Not the fittings, the rear cylinder location is different.

Pat

Ah!

 

[mrsprite]

If the only leak is at the top then replacing that gasket should seal it back up. I haven't used any sort of sealer on mine, but it may help. Mine is just a homemade cork gasket I cut from a sheet and I haven't had any problems with it leaking.

I am also running front disc brakes (and rears) from a later Spridget with the stock 7/8" master cylinder. For the most part it works well, but I have had some braking issues over the past year that were related to the master cylinder (i.e sticky pistons, etc.). My personal feeling is that it should have a 3/4" master. I plan on upgrading as soon as I have the money and after I get my Bugeye back on the road (just swapped out the clutch).

Oh yeah.....you should also change the rear brakes to the later Spridget ones. From what I have heard, the balance of the braking system will be a bit out of whack otherwise. My car was already converted when I bought it, so I have no direct experience with the old brakes versus the new, but I have heard it more than once.....if you swap the fronts to disc, also do the rears from the same donor car.

Good luck.....swap out that gasket and see what happens.

 

[Sarastro]

The to-plate-to-body joint should be easy to seal up; just be sure everything is flat and clean, put in a new gasket, and all should be well. I'll bet some gasket material was left on one surface or another. Just scrape it smooth, check flatness with a metal ruler. Of course, be sure the screws are tight but not overtightened.

 

[Bugeye_Al]

Thanks guys. Since I have pulled the MC, I whink I will go ahead and get it re-sleeved to 3/4". I don't think I will send it back to the place that rebuilt it before. Any suggestions on who to perform the re-sleeving?

Now to source some later rear brakes and try and do this right.

 

[Trevor Jessie]

brakecylinder.com

 

[John Moore]

I sent mine to Sierra. I haven't got it back yet, but I've heard plenty of rave reviews from folks on this board.

https://brakecylinder.com/spridgetbrakes.htm

It's not cheap, but brakes are something I don't fool around with and try to cut corners. I had the place in NY rebuild my MGB MC about a year and 1/2 ago and it's already leaking. I just bought a new MC from Moss. You gotta stop and well!

 

[Trevor Jessie]

too verbose John. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[John Moore]

too verbose John. /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

LOL! I'm serious about stopping! /bcforum/images/%%GRAEMLIN_URL%%/grin.gif

 

[bugimike]

I think Trevor was referring to the "application" /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

 

[Sportsdoc]

Sierra

Got my MC resleeved here with new pistons. I would recommend them.