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MG MGB Technical - Pedal Box/master cyl. dillema

I decided to take out my clutch and brake master cylinders today and ran into a few problems. Problem no. 1: after clearing out the mouse nesting under the brake master cylinder so I was able to get at the nut on the bottom of it, I successfully unbolted it. However, I've come to the conclusion that it's not physically possible to take it out without taking out the entire pedal box - which leads me to problem no. 2: I can't get the pedal box off. somewhere along the line, brake fluid leaked EVERYWHERE at the pedals, resulting in the corrosion of the entire area. I got two of the bolts for the pedal box off, but there are three more that I cannot fathom being able to get out. one is easy to get at, but due to corrosion, it is now actually PART of the pedal box. the other two are nestled in between the box and the inner side of the motor compartment (next to the trumpet section) and are also corroded pretty badly. I can't even get in there with my Dremel to cut the heads off. does anyone have any suggestions? both of the master cylinders are shot and need to be replaced. Also, I can't even get the hydraulic line for the clutch off the master cylinder. it's completely frozen to the cylinder.
Chris

Hi,

You really do need to be able to remove the hard line to be able to remove the cylinder - once it's off the whole thing moves backwards until the back part is poking through the hole in the bulkhead, and then the linkage will come past the pedal box and you can remove the whole thing, forwards and upwards.

Perhaps you should saw the hard line with your dremel, as close to the cylinder as possible?

I hate brake fluid. However, I really really love the name 'trumpet section' so that makes me feel okay again :o)
--
Olly
Oliver Stephenson

My car is out in the parking lot, so I can't check the reality on this, but can't you get to the bottom of the screws from the cockpit? Maybe you could drill out the screws from the bottom end.
Matt Kulka

Chris, if spraying with WD40 and a tight fitting socket (the sort you hammer on) with an extension doesn't work, you might try grinding off the bolts from underneath and drilling them out.
Or some combination of the above. I don't envey you though,
Peter

On both my cars there is a rubber plug in the firewall that enables you to get to the hydraulic line nut from inside the cabin, as well as the mounting nuts.
Paul Hunt

Whenever my nuts or bolts are frozen I use heat - lotsa heat :) I would use a propane torch from underneath the dash so you can see what wires may be close as you wouldn't want to burn any and use a small flame. Not the easiest or best place to use a torch but sometimes you have no other choice. A oxy-acetylene torch with a small head would be even better and you can actually hear the moisture POP! I never met a bolt that didn't come free with a rightous blast from oxy-acteylene.

BTW, can you get to it with sockets? If you can get sockets in there then use a 1/2 impact gun and shear the bolt heads off. After you get the pedal box out you can then use heat or drill out the bolts and use helicoils. Next time use plenty of antiseize. Good luck
Mike MaGee

I did think about getting to them from the inside, but I was under the impression that the bolts were welded on. Also, I'm trying to this with the least amount of destruction as possible. shearing off the clutch line did cross my mind but I'm not looking forward to putting a new one in! I have a very short list for the moment - get clutch/brakes working, batteries in, and motor running so I can properly store my B a garage 3 hours south of here for a full resto. the more destruction I do to the B, the longer it waits to go in a garage! It's under a tarp at the moment and I'm sure that's not a very good idea in Seattle. Oliver - I, too, love to say trumpet section. sometimes I just throw it in for the hell of it!
Chris

Do you mean the bolts holding on the pedal box cover, or the framework itself? The latter are inside the car on the bulkhead and so from your description I think you must mean the former. If so, then I faced the same problem a while back. In the end I bought a really long drill bit (over a foot in length) and drilled the heads off very carefully. My intention was that once the cover was off I could remove the cylinders and framework then drill out the remains of the bolts and re-tap if necessary. Fortunately, the heat generated by drilling off the heads loosened the remains of the bolts, and once the cover was off there was still enough bolt left (and working space) to get a mole grip on and twist them out. Once the whole lot is out you can repaint and place the gaskets, and if you use stainless bolts with copper grease on reassembly they should stay free for a long while. Actually I loosen mine every year now just to make sure I still can!
Miles Banister

If it is the bolts i m thinking off, i ground the captive nuts off from within the car with a grinder, cleaned area, and rewelded new nuts to the bulkhead.
Ian Sanders

I'm talking about the framework. I never found a specific name for the framing of the pedal box. I did think of grinding the captive nuts off but again, I'm trying to do this as timely as possible so I can get the thing into a garage! It would take some time to arrange for someone to weld for me. However, I wonder if I can get vice grips on the other end of the bolt from underneath the bulkhead and twist 'em out far enough to get a grip on the bolt heads with a socket extention.
Chris

I've had a look at the parts book now, and I can see exactly what you mean. I was lucky and didn't have a problem with those bolts. I wonder if you could still use the very long drill bit trick to reach those bolt heads and drill them off? One way or another you're going to have to drill or apply heat to shift them. I think I've seen somewhere a tiny blow torch that jewellers use, maybe one of those applied to via the captive nut end might be enough to crack the adhesion?
Miles Banister

I DESPISE going near the pedal box. Think mine was complicated by a PO who used screws with improper threads which he did in a number of places. Being a PO myself (inadvertently) I put them back in then realized what had happened. Next time in when I paint the engine compartment. I will locate proper screws/bolts.

Gotta go look up "the trumpet section". Too cool not to be able to say occasionally..."just for the hell of it".

JTB
J.T. Bamford

Maybe using a vice grip on the underside to crack the rust will help.
Mike MaGee

I had let it slide, because I figured the problem would be solved by now. But it's worth noting that WD-40 is not a penetrating lubricant. It won't do a blinkin' thing to loosen rusted nuts and bolts - except give them that fresh, pepperminty WD-40 smell.

Get yourself down to the auto parts store and blow $3.95 on a spray can of "Blaster PB." This truly is a penetrating oil, better than Liquid Wrench, my previous standby.

Use some brake parts cleaner to clean off the old brake fluid, loose paint and corrosion, WD-40, whatever. Then when dry, spray in a bit of Blaster PB, tap the parts a bit to get vibration to work it into the crevices, and leave it for a couple of hours. Then go at them with your long extension and socket.

You'll have much better luck with a good penetrant.
Matt Kulka

yes, I've used PB blaster on plenty of rusty situations to absolutely NO avail. so far I have yet to see it do any good... although I would take it before WD-40 any day of the week. also, I've tried the heat technique on other rusted bolts and it also did no good. I got them good and red hot and still couldn't get them off! thanks for all the input, everyone, but I guess it's just going to take a lot of cigarettes, beer, and cursing (not to mention bloody knuckles) to get 'em out.
Chris

Chris, I just pulled my pedal box and I was lucky, none were stuck. However, the clutch pipe was stuck to the back of the master cyclinder. After several attempts with PB Blaster, I heated it up with my torch sprayed PB blaster on the threads and I think the heat helped the PB blaster get deeper into the threads. It came off afterwards.

Good Luck! Stuck bolts are a PITA!
J Moore

I wonder if you could fashion cup shaped objects out of plasticine, and use them to keep a pool of penetrating oil around the captive nuts for a few days?
Miles Banister

Plumber's putty or some such?

Wayne
Wayne Pearson

Why don't you just load the bloody car up on a trailer and haul it down to that garage and spend the upcoming winter taking apart the whole car? Get a head start on the restoration instead of doing breaks now and again later.
Geoff
Geoff Kimler

This thread was discussed between 13/10/2003 and 17/10/2003

MG MGB Technical index

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