70 mgb clutch hydraulics, rebuild or replace on 68k mi car?: Classic Cars forum: Classic Motorsports Magazine

Forums » Classic Cars » 70 mgb clutch hydraulics, rebuild or replace on 68k mi car?

June 8, 2009 4:06 a.m. problemaddict Reader

Hey gang,

I just got my mgb road worthy again after about a year of sitting. As stated the car has 68,000 miles on it. After a few jaunts around town the clutch pedal has started to take it sweet time returning to the up position. It has pressure on the down stroke, but slowly returns.

I'm assuming a problem w/ the clutch master or slave or both. With only 68K on the car, do you think the available rebuild kits would be appropriate, or should i replace one, the other, or both (at significantly higher expense!)?

Thanks for any experience/advice,

Mike
June 8, 2009 7:53 a.m. Tim Baxter Online Editor

I usually try to rebuild 'em. Rebuild kits are cheap, and MG cylinders usually aren't.

Doesn't always work though.
June 8, 2009 9:29 a.m. Carl Heideman

At Eclectic Motorworks, we usually rebuild both units at the same time. If one's failing, the other will fail soon--although the slaves fail more than the master cyls. Don't hone the master cyl--it's anodized and will get porous if you hone it. Just clean it really well and put the new rubber in. If it's scored badly, replace.

People complain that bleeding is difficult sometimes--it isn't if you take your time. We wait about 30 seconds between "bleeds" and it usually takes about 5-8 times to get the air out of the system. Don't pump the pedal when you bleed, just one down stroke at a time per bleed.

--Carl
June 8, 2009 4:46 p.m. problemaddict Reader

Thanks guys! That's a releif. I wasn't excited about spending the money on the replacements. I'll try the rebuild kits.
June 8, 2009 7:45 p.m. Shinsen774 Reader

Check the position of the bleeder on the slave.....they often ship it in one hole, when they should be installed in the other.
June 9, 2009 12:27 p.m. OFracing New Reader

I seem to get about a 50% yield rate on rebuilds. I usually try a rebuild first unless there's a obvious problem, like corrosion.

Just remember, some of the OEM rebuild kits have rubber parts that are 30+ years old too. Check them out before you use them.

mike
June 9, 2009 4:40 p.m. Jensenman MegaDork

Check carefully for corrosion. Use a penlight or similar to get a really good look inside the bores. Water has a nasty habit of collecting at the bottom of the bores and leaving rust pits which render the casting pretty much unuseable. Pitting = replacement.
June 15, 2009 4:20 p.m. problemaddict Reader

Well, i got the Clutch M/C out and it looks a good bit corroded on the bottom Bummer. Which leads me to a search of M/C's for sale.

RockAuto has "Rhino Pac" master cylinders for a whopping $31!! Anyone use this brand before? Google gives me many places selling them, all between $30-=50. But Google doesn't give me any links to ppl who have used one. Encouragingly there's no horror stories posted either...

So, what's the deal? are they made out of balsa wood or something?

-Mike
July 4, 2009 12:43 p.m. problemaddict Reader

Hey,

Well, the Rhino Pac stuff showed up. Guess what? The master cyl is stamped "LOCKHEED MADE IN ENGLAND" just like the original.

Anyway, i guess Rhino bought up a bunch of NOS stuff? I dunno. I installed both the master and slave cyls yesterday and the clutch is workin' fine now. And during the job, i found a ton of rust in my floor! yay!
July 4, 2009 11:18 p.m. GSCReno New Reader

More likely that the Chinese have bought Lockheed... Glad that you've got it sorted... That's one more classic car on the road. Cheers, Scott