The BORA

Thank you Bob, I'm grateful for your knowledge and experience here.. Below is an "at speed" photo from an outing I took yesterday, maybe the rear is squatting a little, but I will check the geometry of the A-arms as you suggest... and I'll perform another detailed visual inspection of all things Front and Rear Suspension up on a lift if I can.

I had the Bora out yesterday for a Social Distancing Cruise. I felt comfortable the trip wouldn't inflict much irreparable harm. It was a good 150miles' worth, over medium to rough secondary road conditions, up to 120mph.. and I didn't notice any significant worsening of the "vibration" symptoms. But one subtlety emerged.

- The main symptom is an audible "rumbling" noise and vibration when driving straight, or taking Left turns. The rumbling noise is what reminds me of a bad bearing. There symptoms go away and the car feels smooth when she is turned to the Right. It "feels" like it's coming from the right side of the car, mostly evidenced by the rumbling noise.
- THE SUBTLETY: You know how an aged secondary road often has two tire-ruts worn into the pavement by everyday drivers? If I place the car on the road such that the left tires are on the center Crown of the road, and the right tires are on the 'crown' that exists between the two 'ruts' worn by everyday drivers, the noise and vibration also go away. This position on the road should result in the car experiencing very 'neutral' driving forces upon the tires. I would expect the same 'neutrality' of forces when driving in the ruts as any other normal driver, but in that position the noise and vibration persisted.

Even if it doesn't tell me much where the problem is located, I think this reinforces that road forces affect the symptoms. Probably less likely to be an engine mount. I believe it's a matter of investigating the pathway that road forces take through the car. Going back to basics, the front right bearings seem the likeliest fault, and I will scrutinize them, but I don't feel any symptoms through the steering wheel.

Thank you for the ongoing conversation on this.
- Art

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The front right wheel bearings were the problem. The inner bearing, so be specific. I'm surprised that none of the vibrations were felt through the steering wheel, but so be it.

Maserati Bora Front Wheel Bearing Replacement. Reference Table 21 for Parts numbers below.

Raise the front of the car. Remove the wheel.

1.) Unbolt the brake caliper (2 x 19mm bolts), and move it aside without disconnecting the brake lines. I used wire to hang it from the shock tower.
2.) Remove the spindle's cotter pin #39 and outer 24mm castle nut #22 and washer #23.
3.) The hub #25 with the brake rotor still attached pulls off with an axle puller bolted to the lug studs. Mine required only gentle persuasion with a slide hammer to come off the spindle. (I used Saran Wrap to temporarily protect the exposed spindle from debris).
4.) Keep track of the inner tapered spacer #29 and note its orientation.

5.) With the hub #25 off, get it secured so you can unscrew the inner ring nut #28. A removal tool can be fabricated from a sacrificial 1-5/8" socket w 3/4" drive (See prior post #736 above). I was fortunate the tool I made for the rear hub's ring nut fit the inner dimension for the front hub's ring nut.
6.) Notice how flat the surface of ring nut #28 sits compared to the surrounding surface of the hub #25 because you are going to re-install the ring nut to this same level. (Review step 13. below)
7.) Apply thread-release oil to the ring nut #28. I didn't need more power than a cordless electric impact wrench w 3/4" drive to unscrew ring nut #28.

8.) Now you have a hub with both bearings exposed. Insert an appropriate socket or pipe to press out the smaller outer bearing #24. It pushes out easily with a press or light hammer.
9.) The tapered spacer #26 drops out with the outer bearing. Observe that there is no 'seat' inside the hub for outer bearing #24.
10.) Flip the hub and press or tap out the inner bearing #27, equally easy.
11.) Clean all mating surfaces on hub and spacers and apply anti-seize.
12.) Insert new inner bearing #27, it basically snugs into place against its seat in the hub.
13.) Hand-thread the ring nut #28 into the hub to make sure it doesn't cross-thread. When the ring nut is threaded on enough, use the homemade 1-5/8" socket tool and impact wrench to drive it back on very snug. I drove it on as flat as the surfaces appeared in step 6.).
14). Insert tapered spacer #26 in the hub.
15.) Put the outer bearing #24 in place, and gently press it into its bore. Reminder: There is no lip inside the hub to "stop" the outer bearing, so don't press it in with a lot of force.

16.) Insert inner tapered spacer #29 on the spindle. Its correct orientation is for the 'cone' to face outwards, such that it mates to the inner bearing's inner race.
17.) I applied a modest amount of anti-seize on the spindle.
18.) Ease the hub onto the spindle until it seats far enough in to thread the outer 24mm castle nut #22 on the spindle without washer #23.
19.) I used the castle nut #22 to press the hub and bearings fully onto the spindle. Then I removed the 24mm castle nut to put the washer #23 on.
20.) Torque the castle nut #22 until it seats, then I backed it off until the cotter pin #39 could be inserted.

Reinstall caliper and wheel.
Go for a drive.


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Good afternoon all,
Hope you have been well.. Question of the day is about managing heat at the CV joints.
One of the side effects of the exhaust system heat is a build-up of pressure inside the rubber boots and CV joint housing, which over time forces the grease out of the seams, as evidenced by the splatter of grease on adjacent A-arms, underside of spare tire, engine block, etc. The rubber boots are completely closed.

What have you all done to mitigate the pressure in the CV system?

My plan is to pierce the rubber boot at a point very close to the driveshaft, where centrifugal forces are the least, and grease is furthest away. This lets out air pressure when hot, lets it back in when cool.

Any thoughts?
Grazie,
- Art

 

Lots of experience with this one Art. I had my CV boots explode twice out in the middle of Nevada which disqualified me for entry in the Silver State race in my Bora at least. Very frustrating.

A couple of things.

1. The heat from those exhaust pipes that loop next to the inboard joints are the culprits. I've never had an issue with the outboard ones.
I thought it was possibly the boots hitting the pipes for the longest time but I proved to myself that it wasn't the case.

2. Being extremely fastidious and get a good seal is ironically the issue.

3. What I did was to put a 1mm hole in the enter of the cap and glued a piece of 1/8th inch thick, dense felt over it and that sits inside the joint. DON'T SEAL THE HOLE SHUT WITH THE GLUE!
That's enough to allow it to breath but not let dirt and hopefully moisture won't get back in. Since then I've not had a problem but I've also not had the car at full tilt for 45 minutes at a time either. Not possible to do that in NJ for whole lot of reasons.
Others have taken the plastic pipe from a Brakeclean spray can and slipped under the boot and clamp at the smaller end. I can't vouch for how well that works.

4. I met a couple of guys from Sacramento who modified their Bora with a custom manifold and they were racers as well. He found silicone versions of the boots, just a basic BMW 6 or 7 series boot from the mid 1970s. Not a bad idea but I haven't done it as yet.

 

Would it be possible to heat isolate the headers? What astonished me most when visiting the McLaren F1 road car factory summer 1995 was the gold foil used for that purpose(!) of course I am not suggesting that solution but how about header isolation (and yes I know no asbestos...).

 

Thanks/Merci both of you -

Marc,
Oui, I have wrapped the exhaust pipes in an insulating material to cut heat radiation.

Bob, in reverse order:
4.) The idea of introducing a thin plastic 'vent' pipe at the "collar" of the boot may have its place.
3.) Your solution - you're talking about a 1mm hole in the center of the end cap that is concealed in the transaxle's drive flange when installed. The end cap being the pressed sheetmetal cap that encloses the end of the CV "chunk". That sounds like a place that will never see grease. Perfect. Not terribly hard to get to. Just the 4 allen bolts at each end and pull the half shaft out. And I can repack it with grease while I have the half-shafts out.
2.) Yes, ironically it's the new fresh boots that are perfectly sealed, that are now forcing grease out of seams that grease isn't even meant to come from.
1.) I also assume it's those inboard loops of exhaust that are the culprit, and my initial direction was going to be to fabricate aluminum heat shields that have worked well for me around the starter motor and gear shift linkages.. but having looked at the geometry involved, that is a far more difficult solution than to vent the pressure.

I will return to this effort in a couple weeks and share results.
Cheers,
- Art

 

Correct.

 

Two more things.

My headers (only) ARE wrapped in in a heat resistant glass fiber cloth which is secured by a winding of SS wire. It doesn't look very nice as it was done in place. It also didn't help with the exploding CV boots which is a hell of a mess to clean up.

Something I thought about but never tried was a SS can slipped over the CV joint with an inner liner heat shield. It would rotate with the joint but I'm not sure about it's being able to fit.
I have double walled brushed SS heat shields that have high temperature heat shielding cloth sandwiched in between and are sealed on the edge with silicone in many spots on my car.
Getting those made was a real treat!

 

I am having a lot of problems re-inserting the front brake pads on my Bora. In order to remove the pads the front caliper needs to come out. The pads slide on two pins which appear to be fixed in place. Under the pads is a steel anti-rattle plate. Only one pad will fit between the pins so they have to be installed one at a time. The problem I am having is the anti-rattle plate is making it impossible for me to insert both pads. There has to be a trick to get this done. Anyone?

Ivan


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Sorry I just don't remember. I don't even remember there being two pins but I'd bet that they have to pushed out. The pistons are fully depressed?

 

Ivan,
If I understand correctly:
- you first insert the anti-rattle plate and fit it in the bottom of the caliper,
- then the first pad can be inserted/pushed down between the pins, the corresponding pin introduced in the pad hole while the pad is pushed sideways and seated properly on its side.

It is then only, when you try to insert/push down the second pad, that you can't push it down enough in order to have the second pin introduced in that pad because apparently the anti-rattle plate still exerts a too strong pressure upwards?

In case, did you check that the anti-rattle pad is correctly positioned in its groove/seat (there seems to be a recess with a corresponding size in the caliper bottom)?
Otherwise, the only way out I see would be to push more strongly on the second pad when introducing it...

 

Bob: Yes the pistons are fully depressed, although it is the pins and the rattle plate, not the pistons, the problem. I do not want to disturb the pins until I am certain that is the only way of getting this done. I do not want to risk bending the pins or they coming loose late.

Serge: You are correct, the rattle plate fits on a groove inside the caliper. The problem is when one pad is inserted and pressure is applied against the rattle plate, the plate moves out of position. If I could insert both pads at the same time the plate should stay in position when force is inserted.

I need to hear from someone that has successfully installed Bora front brake pads and remembers how it was done. Although I appreciate folks theorizing how it could be done I much prefer actual experiences.

Ivan

 

Try calling Andy at Bill McGraths. Or you might try Gene O'Gorman as he may have replaced his Bora's pads more recently.

The Bora and the Pantera share the same front pads and here is a photo of a Pantera front caliper which looks awfully similar so perhaps some Pantera folks would know?

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I think this image has the answer! It appears two screwdrivers are used to tension the anti-rattle plate and hold it in place while the pads are bring removed and inserted. I knew there had to be trick! I'll be doing caliper seals in a few days and will see if this trick works.

Ivan

 

Hope so. BTW my car has Pantera replacement pads WO the wear wire on it. I gave my OEM replacements to a friend one day at the track and got the Pantera ones as compensation ...

EBC makes pads for this caliper!

https://www.amazon.com/dp/B004AHVC7E/ref=au_as_r?_encoding=UTF8&Make=Maserati%7C79&Model=Bora%7C1098&Year=1977%7C1977&ie=UTF8&n=15684181&newVehicle=1&s=automotive&vehicleId=12&vehicleType=automotive

 

..that's a nice clear picture of the setup, hope you got results Ivan.

Now, have you sourced replacement pads with the wear-sensor wire, or even without?

@staatsof; Bob, the Amazon link is the specific pad design that fits the Bora fronts?


It seems like the Bora has a front caliper design ripe for improvement.
- Art

 

I did replace my front pads a couple of years ago but do no remember having this problem. Make sure to check the Aluminum upper a arms as they have a tendency to crack, sometimes at the ball joint but usually on the back of the swing arm.

 

I haven't tried the EBC ones but if it fits the Pantera it will fit the Bora. In the past EBC has had catalogs that show a lot more about pad designs and which cars they fit. That basic caliper design went on a number of cars.

 

My pads (which appear to be the original) do not look that bad and I plan to re-use them. The sensor wire still has all the original fasteners so I doubt they have been replaced. Gene: I will make sure to check out the A arms. The caliper rebuilt kit was delivered in today's mail; this will be one of this week's projects. I am also busy rebuilding a 1961 Morgan Plus 4 (TR3) engine .... but that is for another thread

Ivan

 

I just finished rebuilding the front brake calipers.Working on LHM brakes is such a pleasant experience compared to standard brakes. With LHM all the pistons and bores are like new and parts disassemble easily. I documented the steps and posted them on my website. These steps also help if you are just replacing the front brake pads.

http://thecarnut.com/Manuals/Bora_front_brake_caliper_rebuild.pdf

Ivan

 

That was exactly my experience when I got my Bora with 3K miles on it but it had most sit in a museum for 10 years. I though I should just got through the calipers. A total waste of time.
So did you even need new rubbers????
All of this begs the question ... after seeing how well LHM performs over time why doesn't the automotive industry use that instead of brake fluid? There must be some reason?

 

I have the same blue paint on my calipers. I wonder what that means? LHM caliper???? Someone should ask Cozza.

 

I thought sure I read a few years ago that the blue paint was to identify LHM

 

They should have used green paint

 

1972 Maserati HIGH BID $173,005 USD
Bora 4.7 EST. PRICE $196.07K-$265.27K USD


EXTERIOR Ischia Blue
ARTCURIAL MOTORCARS
INTERIOR Tan
Lot 693 Monaco
ODOMETER 78875 km

CHASSIS Nº AM*117*126
July 21, 2020 2:21PM (EST)

https://www.carandclassic.co.uk/car/C1241762