Leaks and issues

[Adam W in MN]

Alright, Spring has been here for at least 4 weeks in Minnesota and I'm pissed at myself and pissed at the M535i. Pissed that I tackled too many projects over the winter and scrambled to put it all back together. Pissed at the M535i that I seem to fix one issue, and 2 more problems pop up.

Recap: Rebuilt most of the braking system with exception of master and booster. Installed oil and coolant temp senders in oil filter mount and thermostat housing respectively to talk to a gauge that I mounted where the stock vdo clock is inside the fan control on the dash. Put in new/reman ZF steering box. Put in new bushings (that were just gone, evaporated or disintegrated) in the throttle pedal linkage below brake booster.

brakes: After getting all the leaks nailed down from putting in new stainless lines, rebuilding (and replacing one) caliper, I still have brake fluid leaking. Where? From the damned fluid reservoir cap. Mine was pretty old and crusty, so for $25 from the dealer, I bought a new cap with the two sensor leads on there. I installed it last night and rebled system including the clutch. Fluid is still leaking out of the cap. I don't know if there's a bad seal where the center section of the cap with the sensor leads spins as you tighten the cap or what. Using ATE Super Blu.

oil and coolant: My tap for the oil sender didn't go so well and it's leaking out of the side. I have it torqued as far as I dare and have teflon tape over the threads. Still a no-go. Looks like I need a new mount which I should have on the way, but I'm wary about ruining another by drilling and tapping this mount. I might install as is and drive the car and revisit this project later. Or get someone to weld the old mount and fill the hole I drilled and retap it properly. The coolant sender hole I tapped is clean and dry at least.

steering: Put in the new ZF box along with a urethane donut that goes in the steering linkage (available from Ireland Engineering). Damn thing is leaking (Redline) power steering fluid somewhere, maybe out of the pitman arm seal area. Power steering is dripping down by the subframe.

throttle and idle: Drove the car last night around the block a few times. Idle is whacked. Wants to idle high as it did before (1200rpm) which I haven't been able to fix, and now it's worse. Sometimes won't come down from even 2k or 2500 rpm. I don't know what the F is going on. And throttle response is ZIPPY. I must have something off on the linkage arm by the firewall because it takes off after barely touching the throttle. What the hell did I do wrong here? Also what's the best method for diagnosing a vacuum leak? Because that's the only thing I can think of that is causing this high idle. And it must have a monster vacuum leak to be having such a high idle now. Almost like the throttle is sticking. The idle got higher and hangs worse after you drive it longer.


You know when you're frustrated by nice weather and some kind of issue preventing you from driving and enjoying your classic car? Well, I'm there with about 4 issues. If you read this far, thanks for listening to me rant and bitch.

[1st 5er]

The only thing I dare comment on is the vacuum leak.
Using a really good and cheap can of aerosol carburetor cleaner sprayed over suspected areas will usually pinpoint the leak.

Bummer on all the other issues.

We each have our crosses to bear.

[alotawatts]

Adam,
1. If you get pissed enough to sell your car let me know first !
2. Is the little rubber 'Chinese hat' still on the top of the reservoir cap ?
3. Propane works well for vacuum leaks
Also did you sort out the overheating problem ? If so how ?
Good luck
Carl

[Adam W in MN]

Ha, trust me you don't want this bucket of bolts.

Alright, last night I messed with it again and drove it for a bit. Need to bleed the brakes, for wtf, like the 4th time. Sheesh. But at least it didn't leak brake fluid. Yep, that rubber Chinese hat thing is still on there. My old (original?) reservoir cap didn't have that on there. I can only think that the brake fluid eventually sealed the rubber gasket in there where the center section of the fluid cap spins.

I tightened the spring that mounts to the engine mount area on the driver side, i.e. put the spring on a different perch to get it tensioned a little more. I have less slack in the throttle linkage now which is good and seemed to keep the idle from going so high. But it's still idling at 1200rpm+ so I need to do the vacuum leak test with my propane tank.

For the cooling issues last year, I finally drained all fluid out of the block and radiator, took the thermostat out and tested it in boiling water and watched it open. Then when I put it all back together and bled the system, it was fine. Even now after the winter and draining everything again for all this work I'm doing, at least it's not leaking coolant and not overheating! If it did I think I'd have a for sale sign on it outside in my driveway.

I tightened the power steering fluid hose clamps even more (really f'ing tight now) so we'll see if that stops the leakage. But I still think it might be coming from the seal down by the pitman arm which would really be a PITA.

Oil is still leaking from where I drilled and tapped the sender by the filter mount so that has to get fixed. Can't drive it too long since it's slowly dribbling nice, green Brad Penn Racing oil down from there.

[Mike W.]

Ha, trust me you don't want this bucket of bolts.

Bucket of bolts??? I thought it was your pride and joy!

Brake cap leak: is the strainer bucket in there? The rubber cap on top was my first thought, but you've got it covered, but if the strainer is missing it might be sloshing around more and prone to a little weekage when driven.

On the throttle, you should have a spring down by the gas pedal, the one on the motor mount where it changes direction and one or two up on the throttle body itself. Are all 3 there?

On your oil sensor fitting leaking, I've epoxied oil pressure switches in the head before, JB weld is a good thing, with out any problem. There was some bite on the threads, but anything more than about wrist tight and it would keep turning. Epoxy to the rescue and it didn't leak a drop afterwards.

Leaking steering box, by the pittman arm? I'm sorry, so sorry. I hear it's no fun at all to pull that arm. It's one of the few things I've never done to these cars, I've just replaced the box if they've been leaky.

[Adam W in MN]

Yep, the brake fluid strainer is in there. Hopefully it will stay dry now that there is brake fluid around the rubber seal.

Good thought on the JB Weld. I guess I don't have any intention of ever removing the sender, so what the hell? I really don't want to do the whole drill and tap affair over again.

Yes, all three springs are there. I *think* that increasing the tension on the one by the motor mount to the block did the trick. It was probably fine before with less tension simply because I had no idea my pedal assembly was missing those rubber bushings where it pivots in the firewall mount. It's amazing what you see when you have the brake booster and master cylinder out.

I really, really hope it isn't leaking by the pitman arm. It wasn't fun, but it wasn't too awful removing it when I had the whole steering box out of the car and I was able to hammer on it out in my driveway. Doing it in the car ......... *shudder*.

[Adam W in MN]

Update, idle is still slightly high, but back to what it has been since last year (about 1200rpm).

I took the temp sender out of the oil filter mount and used a copper crush washer and high strength Loctite all around the threads and crush washer. Zero leaks now (YAY!).

Still getting brake fluid leakage around the reservoir cap. Really pissing me off. I'm going to take a closer look at the gasket and try to find out if something is getting pinched.

On another weird note, car is pinging a bit at full throttle higher rpm's. Nothing has changed regarding timing since last year. The local BP started carrying 93 octane so maybe that will help (92 is in the tank).

[Mike W.]

Update, idle is still slightly high, but back to what it has been since last year (about 1200rpm).


On another weird note, car is pinging a bit at full throttle higher rpm's. Nothing has changed regarding timing since last year. The local BP started carrying 93 octane so maybe that will help (92 is in the tank).

You know both those things point to advanced timing. I'd check it again, but I've only ever regarded the factory spec as a guideline anyway. And you can always adjust the idle speed too.